Hearts of Iron IV has a lot of different units, but many of them are seldom used. Partly because some units exist for historical authenticity and are bad in-game because they were bad in real life. But some units are ignored by players simply because they’re too niche, require too much investment or players don’t know how to use them. Furthermore, most guides regarding the division designer only bother with explaining the most essential units. This works for novice players, who are still learning the ropes of the game. But let’s say you’re an intermediate player. You know how the core mechanics work and you want to start making your own divisions without relying on guidelines. Maybe you also want to explore some of the wackier builds and get experimental? In that case, this guide is for you.

An important warning before we start, this guide is NOT targeted for beginners who are learning the basics. This guide is operating on the principle that you know the core mechanics of the game and really want to learn the ins-and-outs of the division designer without restricting yourself by whatever is meta. I won’t go into much detail about any ideal division setups, best combat widths or what is best to use if you want to win. This guide is for those who want to experiment and have fun, and almost all units are viable in that regard.

Some other important things to make clear before we start is that this guide is meant for vanilla unmodded HOI4 as of version 1.14.X with all relevant DLC active. (MtG, LaR, NSB and AAT are the main ones you’ll want.) The vast majority of this guide is also designed for singleplayer, but the information present should still work for multiplayer. Lastly, this guide should not be taken as gospel and more as an introduction for you to learn more by yourself. Don’t take what I say as absolute fact and don’t be afraid to ignore what I suggest.

When I first got into HOI4 and started learning things, I frequently used a guide on the Paradox Forums about unit types and division design. It was very outdated and too complicated for me to make too much use of, but I still found it very helpful for kickstarting my learning of the division designer. You could consider this guide as a tribute to it.

Before we start, it’s important to make sure you know the fundamentals of the division designer with the statistics that any division has. There are honestly better guides out there for explaining this, but it is important to quickly cover here as to make sure that we’re on the same page. I’ll also cover the abbreviations that will be used later in the guide. If you know all this already, you’re free to skip this section.

The stats for any division are visible on the right side of the division designer both in the army planner and when inspecting a deployed division. The stats shown in the army planner are theoretical stats going off the best-case scenario, while the stats shown in the deployed division are the actual stats that the division has in its current status. These stats are divided by the game into three categories with each category occupying a different column. Said categories are Base Stats, Combat Stats and Equipment Cost.

• Maximum Speed (often just called speed or SPD): The default speed of the division, calculated by the slowest unit present. Minimum theoretical value is 4km/h while the minimum practical value is 1km/h. Higher SPD is incredibly useful but always carries downsides.
  
  
• HP (Short for Hit Points): How much damage a division can take before it loses all equipment and manpower. Largely the same as Strength, which represents how much a division is fully supplied with manpower and equipment. Calculated by the sum of all units. Higher HP means fewer losses from taking damage, since more damage to HP is required per equipment/manpower. This stat is the main reason why pure artillery and pure tank divisions do not work.
  
  
• Organization (ORG): Effectively the combat health of a division. Divisions without any ORG will halt offenses and retreat from defences if possible. Calculated by the average of every unit. Higher ORG lets a division stay active in combat for longer.
  
  
• Recovery Rate (RR): How much a division recovers organization hourly outside of combat. Calculated by the average of every unit. Higher RR cuts down on recovery time for divisions, letting them re-enter combat quicker.
  
  
• Reconnaissance (Recon or REC): A stat mostly tied to the Recon support company. Having superior REC makes it easier to get Initiative in a battle. This means your side picks combat tactics after the enemy, which increases the probability of using a counter-tactic. In-game description also says it increases intel gained from land combat.
  
  
• Suppression (SUP): How effectively a division can reduce resistance in an occupied state. Calculated as the sum of every unit and only important for resistance garrisons. The higher the SUP per unit, the better.
  
  
• Weight: How many convoys the division requires for naval transport and how many transport planes the division requires for paradropping. Calculated by the sum of every unit. Mainly important for special forces.
  
  
• Supply Use (SU): How much supply the division consumes daily. An SU greater than the supply available results in a deficit which inflicts widespread penalties. Calculated by the sum of all units. Lower SU is always better, but its importance heavily depends on where you’re fighting.
  
  
• Reliability (REL): Shown in-game as Average Reliability, since it’s calculated by the average REL of the equipment used in the division. REL reduces the likelihood of losing equipment from HP loss and attrition. Increases in importance with the cost of equipment and has no effect above 100%.
  
  
• Trickleback and Experience Loss: Stats both tied to the Field Hospital support company. Trickleback returns a percentage of manpower lost during combat while Exp. Loss reduces experience lost from recovering manpower. Higher trickleback and lower exp. loss is better, as the former works from positive percentages while the latter works from negative percentages.

• Soft Attack (SA) and Hard Attack (HA): How much damage a division can deal every turn during combat in the form of SA or HA. Calculated by the sum of every unit. SA is better against low HARD divisions while HA is better against high HARD divisions.
  
  
• Hardness (HARD): The meter visible under the statistics sheet. HARD is the ratio between how much SA and HA is taken as damage. 0% HARD means all damage is from SA, 50% HARD means a 50/50 split and 100% HARD means all damage is from HA. Calculated by the average of all units. Almost all divisions deal more SA than HA, so higher HARD is usually better.
  
  
• Air Attack (AA): Reduces the effectiveness of enemy Close Air Support (CAS) by up to 75% and can shoot down enemy planes on CAS missions. Calculated by the sum of all units, although in combat it is calculated by the average of all divisions involved. Higher AA mainly affects the number of planes potentially shot down, since the other effect is capped at a very low value.
  
  
• Defense (DEF): How many opportunities a division gets to avoid an enemy attack while defending. Calculated by the sum of all units. High DEF makes a division less likely to take damage on the defence, letting them hold for longer.
  
  
• Breakthrough (BRK): Defense, but for the attacking side. Calculated by the sum of all units. Having units/divisions with high BRK is incredibly useful on the offense.
  
  
• Armor (ARM) and Piercing (PIER): If a division’s PIER is lower than the opposing division’s ARM, then the armored division takes less damage and deals more damage. This modifier scales in fixed thresholds with the relativity of the two stats. Up to 50% if the PIER is less than half of ARM and down to 0% if the PIER matches or exceeds ARM. Both are calculated by adding together 40% of the highest value in a division with 60% of the average value in a division. The bonus from ARM is incredibly powerful, so being able to counter it can be equally powerful. Higher ARM is always better while PIER needs to only match the ARM of the opposing side.
  
  
• Initiative (INIT): Not to be confused with initiative regarding combat tactics, INIT is tied with the Signal Company support company. It provides a multiplier to planning speed, RR, and the hidden stat coordination. It is one of the only ways to improve the latter two.
  
  
• Coordination (CORD): Hidden stat not visible in the division designer. CORD modifies how divisions distribute their attacks in combat so that more is concentrated on a singular division rather than evenly distributed. Can only be increased through radio/radar research technology and INIT.
  
  
• Entrenchment (ENT): Increases the maximum entrenchment that a division can have. Divisions will increase ENT whenever they’re stationary, providing a bonus to attack and defense if defending. ENT is instantly lost when a division no longer remains stationary. Calculated by the sum of all units. Incredibly useful on the defence but worthless on the offense.
  
  
• Equipment Capture Ratio (ECR): A stat tied to the Maintenance Company support company. Let’s you steal a certain percentage of equipment lost by the enemy during combat. The amount is never significant but can help reduce equipment losses, especially on the defence.
  
  
• Combat Width (CW): How much space a division takes up in the battlefield. Calculated by the sum of all battalions. Allowed maximum CW depends on terrain and how many directions the fight is taking place in. Exceeding maximum CW results in penalties and blocks new divisions from entering combat. Extremely important as it is often the main thing determining division composition.

Equipment cost is mainly a list of all the manpower and equipment required for a division to be at 100% strength. That being said, there are still some important stats from this list that deserve further explanation.

• Training time (TT): How quickly a division gains experience from deployment training and on-field training. Calculated by the highest value present. The lower the value, the quicker a division can be trained and deployed.
  
  
• Fuel Capacity (FC) and Fuel Usage (FU): FU is how much fuel a division consumes when needed. Divisions connected to your supply lines consume fuel directly from your fuel storage while divisions not connected consume it from their internal FC. If either of these run out then the unit will suffer up to -60% to speed and -90% to combat stats. Calculated by the sum of all units. Importance depends on the availability of fuel, and you should preferably avoid having any FU at all if possible. High FC can be a good way to compensate for high FU, but FC is difficult to raise.
  
  
• Production Cost (PC): Technically not a stat, but nevertheless important. PC refers to the cost of producing an equipment and by extension the cost of maintaining a unit with said equipment. PC relative to other stats is often the best measurement of how cost-effective an equipment is.

One last important thing to talk about is what constitutes as early-game, mid-game, and late-game. This is something that doesn’t have an agreed upon definition as far as I know, so I’ll define it by early-game being between 1936-1940, mid-game being between 1940-1944 and late-game being everything after 1944. Each of these sections have a pretty distinct flow of gameplay and the usefulness of certain units change with them.

There are 44 unique battalions and 28 unique support companies in the game, totalling 72 unique units. This list will cover each and every one of them. Some descriptions will be brief while others will be long. Some units will be grouped together while others will be covered separately. To keep this list coherent, units will be categorized as they are in-game. I will also list up to three strengths, weaknesses, and best use cases for every unit to give a brief summary of them. It goes without saying that this list will be long, and you don’t have to read all of it in one sitting. Feel free to skip around and only check out what interests you most. Just because this breakdown is exhaustive doesn’t mean it has to exhaust you.

Infantry battalions make up the bulk of most armies and are generally the most common category that you will encounter. It consists of infantry and eight variants that all share the same fundamental characteristics. So the features that define this category are found in its namesake unit:

Infantry is the bedrock for combat in HOI4. The characteristics it has defines the flow of combat and is the origin for roughly a quarter of all battalions. This makes infantry quite paradoxical to describe. As what differentiates it from other battalions is also what differentiates other battalions from the norm. Infantry is the default; so what is the default?

Infantry is defined primarily by three things: High ORG and RR, high DEF, and low PC. This makes them innately stubborn on the defence, especially for their price. Infantry’s mediocre SA and poor BRK then means that the defending side will always have the advantage in an equal fight. You could compensate through superior numbers, but infantry also happens to be one of the most manpower-demanding units due to their low PC and general softness. Plus, this isn’t WW1. This is WW2. We have trucks, planes, tanks, and new doctrines that exist to break the stalemate of infantry-only warfare. Although infantry will still make up the bulk of the front, it no longer needs to carry it.

Infantry divisions should be what a front primarily consists of. They excel on the defence thanks to their DEF and ORG relative to PC but struggle on the offense without the help of artillery, CAS, and support companies. A beefed-up infantry division can be a mighty mean division, but it often losses its flexibility and low PC in the process. As such, it’s more common to primarily use more well-rounded infantry that make use of favourable conditions to win a fight. This infantry can then support more offense-focused divisions through pressure tactics and soaking up damage. Infantry is above all else a template that other units are added to. It’s often only used by itself when nothing else is available.

Bicycle battalions are effectively a mobile battalion in another category. Its design is very similar to Cavalry: A faster moving but more expensive and less flexible version of infantry. However, while cavalry only requires 20 more infantry equipment, bicycles instead require 10 support equipment. This makes bicycles the most expensive infantry battalion in the game and usually too costly to be regularly used in the early-game. Bicycles are also only available to a few countries, further limiting their usefulness.

That being said, they do gain some purpose in the mid- to late-game. Unlike cavalry, bicycles count as infantry for the sake of bonuses from land doctrines and technology. Meaning bicycles generally take the place of cavalry once the latter falls out of favour. By the late-game, you may also reach a big enough industry that the increased production cost becomes negligible. Letting bicycle battalions have a niche use-case as a late-game ‘elite’ infantry.

I’m grouping these together because they all serve a very similar purpose: They're slightly altered infantry battalions that are only available to a select few countries in locked templates. This gives them extremely limited use-cases, as the few countries with access to them can’t even use them in the division designer. They do still have some unique functionality, so it’s worth quickly going through all three and what they can be useful for.

• Penal Battalions: Obtainable through the USSR, Finnish, Brazilian and Paraguayan national focus trees. Better ORG, RR and PC at the cost of lower HP and the worst SUP in the game. Treat them like normal infantry.
  
  
• Irregular Infantry: Lowest TT and PC in the game. Has terrain bonuses but is worse than infantry in every other way. Meant for Ethiopia. Use them in desperation.
  
  
• Militia: Identical to infantry with very slightly lower ORG and TT. Gimmick unit for Italy. Can be slightly improved through their national focus tree.

Special forces infantry have slightly better stats and unique features at the downside of higher PC, higher TT and being limited in numbers. Mountaineers and Marines have identical stats while paratroopers have slightly higher HP, higher TT, lower PC and less BRK in comparison. All special forces also have access to technologies that gives them even better stats and they have unique special forces doctrines if you own Arms Against Tyranny. This means that with the exception of paratroopers, special forces are well-suited to act as elite infantry for compositions too expensive or detrimental for regular infantry.

The main appeal with special forces, though, are the things unique to each of them. Mountaineers have terrain bonuses for hills and mountains. Marines have terrain bonuses for amphibious assaults (i.e. attacking from a naval invasion,) alongside rivers and marshes. And paratroopers have the unique ability to drop/attack from the sky with the help of transport planes. Mountaineers and marines have very similar use-cases: If you’re going to fight in terrain that they’re meant for then it helps to have them. Marines also have a variant, Marine Commandos, that is unlocked through their doctrine and is able to exfiltrate from any coastal tile.

Paratroopers on the other hand are a bit more complicated regarding their use case. Paratrooping is very risky. You’re either sending the division directly at the enemy without any way to retreat or deep into enemy territory without any easy way to return. Paratroopers are very likely to be lost, so most people don’t bother supplying them with expensive equipment and support companies. The most common use cases I’ve seen for paratroopers consist of two things: Performing naval invasions from the sky or RAT BRIGADES. Rat brigades consist of divisions with just 1 paratrooper battalion that are sent en-masse at the enemy to capture victory points, destroy supply lines, steal territory, and just cause general chaos. These divisions are not made to come back but can potentially do a lot in their short lifespan. The paratrooper doctrine even gives you bonuses that encourage this kind of strategy. Plus, if you steal an air base, you can potentially send transport planes in to escort the paratroopers out.

Mobile battalions consist almost entirely of units derived from infantry with better speed and slightly better offensive stats. This category serves both as an intermedium between infantry and tanks while also having some of the strongest (and most expensive) forms of infantry in the game. It is for this exact reason that the mobile battalions are commonly used in breakthrough divisions to improve ORG and HP while retaining high SPD and good offensive stats. Although most of these battalions still work well on their own.

Cavalry was on its way-out during WW2 and that is heavily reflected in HOI4. Compared to regular infantry, cavalry has a better speed of 6.4km/h and higher ORG, SUP, TT and PC. It also has some pretty negligible terrain maluses. While the difference in SPD may not seem like much, it can do quite a bit in certain situations. It’s quite common for cavalry to be used to suicide rush victory points in early wars and civil wars for a quick capitulation. (A strategy that is commonly called snaking.)

However, much like in real life, cavalry falls off pretty hard later into the war. Partly due to the increased availability of stronger mobile battalions, but primarily because it is in a unique category and thus receives separate bonuses from infantry and motorized/mechanized. This difference is subtle for technologies, but extremely apparent for land doctrines. Resulting in cavalry usually being outperformed by infantry later on and best suited for niche use-cases like resistance garrisons. As a resistance garrison, cavalry is extremely powerful. As it has the best SUP in the game relative to PC.

Fun little history lesson for HOI4: Before the release of Arms Against Tyranny and the accompanying patch, cavalry had twice the SU of infantry. This was removed to make cavalry a bit more viable, but they forgot to bring that change to camelry!

Camelry is a variant of cavalry only available to a few countries. It’s worse in most ways but has slightly better terrain modifiers, mostly regarding deserts. It also has unique graphics and is kind of funny. There’s nothing more to it than that.

Motorized Infantry are the cheapest battalion that require fuel. While their PC is pretty average on a broader scope, it is very low for a fuel-consuming unit. This makes them quite prone to emptying your fuel supply if you deploy as many of them as possible. But outside of that problem, they are generally quite easy and enjoyable to use.

Motorized isn’t strong enough to be a full-on breakthrough unit, although their BRK stat is pretty good for a unit based off infantry. Their biggest strength is that they are fast. Very fast. Fast enough to cause absolute chaos if they break through enemy lines. This speed, alongside their decent BRK, means they’re often used in early tank divisions as a substitute for mechanized or with light tanks that are too cheap for mechanized. If used by themselves, you absolutely want to abuse their SPD as much as possible.

Mechanized Infantry are strong. Arguably the strongest version of infantry in the game, but also the most expensive. They’re often relegated to being used in tank divisions because of that cost. However, they are very capable by themselves. Having some of the most well-rounded stats in the game and arguably being the cheapest unit with effective ARM and HARD. The biggest problem with mechanized are that they lack the insane attack stats of other breakthrough units while still suffering from their downsides. As much as mechanized wants to be a breakthrough unit, they are still infantry. It’s better to treat a division of them like a super beefed-up infantry division rather than a full-on breakthrough division.

Something notable about mechanized is that their equipment, Mechanized Equipment, is one of only equipment in the game with upgrades enabled if you own all DLC. This lets you do some wacky stuff with them in the late-game if you got the land experience for it. Like reducing their PC by 25% without penalty or having their SPD exceed that of motorized. Simply click the ‘Create Variant’ button on them in the production menu to access it.

One of the biggest problems with marines is that they sometimes aren’t strong enough. Sometimes, a position is so well-defended that infantry can’t penetrate it. But what if we could take a stronger version of infantry and make it into marines? The result are amphibious tractors; Amtracs. Although they’re only available if you own Man the Guns.

Fact of the matter is that most naval garrisons tend to suck. Usually relying on the difficulty of naval invasions to compensate for lacklustre stats. This is something that marines exploit, but it also means that marines are pretty easily beaten by any good naval garrison. Amtracs, effectively the marine version of mechanized infantry, overcome this issue. Having all the terrain bonuses of marines while based off the much stronger mechanized infantry. Amtracs can accomplish what marines can’t. Although they are only really necessary in PVP multiplayer, as the AI is notoriously bad with naval garrisons.

While amtracs can be very powerful, they come with significant drawbacks. They’re very badly restricted by special forces capacity as they require unique expensive equipment that can easily go to waste once you reach the special forces limit. Their stats are also worse than mechanized, meaning you really have to bank on the naval invasions to make them worthwhile. They’re generally best suited for countries where naval invading is expected or where special forces capacity is rarely an issue. Good examples include USA, UK, or Japan. They’re also practically mandatory if you’re planning to use amphibious tanks, but we’ll cover those in more detail later on.

The unit whose equipment you’ve seen a million times but likely never used. Armored Cars require La Résistance and are meant as a sort of a middle-ground between motorized and mechanized infantry. Only problem is that they got greedy and decided to become a breakthrough unit too! This means that their HP, ORG and DEF is utterly terrible, and they need support from motorized or mechanized infantry to be remotely effective. It also takes until the 1940 version for their ARM to even work against basic infantry. While their one shining grace, that being their offensive stats, isn’t even good enough for them to act as a proper breakthrough unit.

It might sound like armored cars are terrible, but they do have their uses. Their SUP is among the highest in the game, which combined with their ARM makes them the best resistance garrison for minimizing manpower usage. Their variant for the recon support company provides the best REC in the game. They have access to equipment upgrades which can be used to get the highest SPD in the game. And their 1942 anti-tank variant fills the very niche role of a budget tank-destroyer.

If you can take all of these random things that armored cars are really good at and make something out of them that is competitively viable, you will have reached the highest echelons of HOI4 division designer mastery. If you can’t do that, then you can still use them as one of the most fun niche units in the game.

This category comprises 4 battalions that are all designed to beef up attack stats and/or counter something. They all have some of the worst HP, ORG and RR in the game but balance it out with heaps of damage in one given field. They’re also among the only battalions with uneven CW, which makes them very common for CW min-maxing.

Each of these 4 battalions have support company variants that are more commonly used, so the battalion versions are often given the prefix “line” to distinguish them. It’s also fairly common for this entire category to be called line artillery instead of combat support.

"Our manpower is precious, bullets are cheap."

Artillery fulfils a very simple goal: Provide a big boost to SA at an ORG, RR and PC penalty. It also provides some meagre stats elsewhere and has the additional downsides of a notable SU and some terrain maluses. The boost to SA is most helpful for infantry and their derivatives since they tend to lack SA and can easily tank the ORG decrease. But this comes at making the division less flexible and resilient due to all the downsides. There’s a fine balance you need to tread in adding artillery to infantry divisions to make the advantages helpful but not overweighed by the disadvantages.

Arguably the most infamous thing about line artillery is its unique CW of 3. This is a double-edged sword with a lot of complications. The CW of all terrain, if we include additional directions, is divisible by 5 but not 2. Meaning a division with CW that ends in 5 rather than an even number can utilize as much CW as possible on all terrain. But using uneven CW entirely changes how you have to plan and design your divisions. You could always just settle for having the CW be one unit higher or lower than you want. But doesn’t that also just feel wrong?

The CW, alongside the general downsides of line artillery, is usually why most people just stick to the support company version instead. That version can be put on basically any division without problem, while line artillery requires you to design the division, and maybe your entire army, around its inclusion.

Anti-Tank, true to its name, counters tanks. It provides a big boost to HA and some of the best PIER that you’ll find outside of tank-destroyers. This comes at the same downsides as other combat support units alongside a higher-than-average PC and the fact that its usefulness entirely depends on the enemy you’re fighting. Similar to line artillery, most people prefer the support company version as it’s cheaper while still providing great PIER, which is often the main draw.

The PIER is generally strong enough to break anything below a heavy tank. The HA isn’t as impressive but good for the PC. Anti-tank is best suited for infantry since they are in most dire need of anti-armor. Anti-tank also has a CW of 1, which can still be annoying but is significantly easier to work with. If you’re up against an enemy that uses armor, adding anti-tank to your infantry can be vital. Its use-cases elsewhere is a bit more contentious, but it’s still the cheapest and most versatile anti-armor that you can get.

Anti-Air is generally the easiest way to get AA on any division. AA helps with countering CAS and shooting down planes. The former is achieved equally well with the support company version and is the main draw of the stat, leaving the battalion version with some interesting niche use-cases. It can either maximize AA to shoot down as many planes as possible, act as budget anti-tank thanks to the surprisingly good PIER or exist just to provide 1 CW.

An important thing to understand about divisional air attack is how it calculates things. The chance to shoot down planes is fixed, while the percentage of planes shot down is randomly chosen from the minimum possible percentage (equivalent to one plane) to a maximum percentage that is determined by the AA stat. This means that the effectiveness of AA, especially in higher values, is very RNG-reliant and can theoretically vary from shooting down one plane to downing the entire airforce. How effective this is at countering enemy air is debatable. You’re sacrificing PC that could be put into an airforce and worsening your land units just to be able to shoot down CAS. But, if you fully invest into it, you can get big results.

The other two use-cases of anti-air are more flexible but not as bombastic. Anti-air sports a surprising amount of PIER that can generally break anything below a medium tank while also being cheaper than anti-tank. Making it a great budget alternative for countries that have to contest against both a superior airforce and armored divisions. This also makes it arguably the best combat support battalion for accessing uneven CW, as it requires the least investment while providing the most versatile stats.

Unlocked later than the other combat support battalions, Rocket Artillery is extremely similar to line artillery. The main differences are that rocket artillery provides slightly more SA and BRK with worse stats elsewhere, including a higher PC, and is more weighed towards late-game thanks to its technologies.

Rocket artillery is not the best in its battalion form. While technically better than line artillery against infantry, it is rarely worth the investment due to being worse elsewhere. Especially since line artillery synergizes best with infantry that are lacking in the areas that rocket artillery are worse in. Rocket artillery's support company version on the other hand is a lot better, but it will be covered later. As such, the battalion version is generally only best used over line artillery if you have an excess stockpile of rocket artillery.

Mobile combat support is a category that consists of four basic variants and one battalion so unique that it completely outshines the variants. So, to keep things short, I’ll cover the four variants together and the battalion by itself. These four variants are motorized artillery (MA), motorized anti-tank (MAT), motorized anti-air (MAA) and truck-drawn rocket artillery (TDRA). They’re motorized versions of combat support battalions. That’s it.

The four variants should generally only be used in pure motorized and mechanized divisions. Tanks are better off with armored combat support while infantry are better off with regular combat support. Their only real difference in strategy is that the SPD allows you to make full-on counter divisions with anti-tank or anti-air. So rather than giving your entire army an anti-tank/anti-air battalion, you can funnel it into one division template that runs across the frontline and counters armour/CAS wherever it appears. This is a very micro-intensive and high-risk, high-reward strategy. It’s also not applicable to line artillery or rocket artillery, as you’re better off with motorized rocket artillery to fill that niche.

Motorized Rocket Artillery (MRA) is a bit of a practical oddity. On the surface, it’s a slightly stronger truck-drawn rocket artillery that is balanced by requiring unique equipment. But this small change is enough to turn its main use-case from a support unit into a breakthrough unit. Filling a role that is one-of-a-kind and incredibly interesting.

MRA, unlike other breakthrough units, completely lacks ARM and has barebones HARD. To make up for this, it has an absolutely insane SA relative to PC that only gets higher with the right technologies. It also sports respectable BRK and great SPD while having better DEF and SU than its contemporaries. As for the downsides, it barely gains any improvements from land doctrines due to being considered line artillery and is very late-game weighed due to how much it’s affected by technologies. It also has lower HP and RR than tanks while being even more fragile due to the lack of ARM and HARD.

It’s easy to imagine MRA as non-armored SPA, but it occupies a very different niche. It’s a late-game centred, budget SA breakthrough unit that sacrifices the durability and individual performance of tanks for overwhelming SA and strength in numbers. This is an extremely niche use-case that is perfectly meant for a mid- to late-game USSR pivoting from defence to offense. As the USSR has the exact right industry size, time-frame, and frontline width to amass a horde of MRA divisions to wreak havoc on the enemy. This is really the only consistent scenario where the MRA excels. It’s fairly unique as a breakthrough unit in that it’s heavily tailored towards exploiting advantages rather than creating them. This makes it very strong for a late-game eastern front, but also makes it very difficult to use elsewhere without it just feeling like an inferior tank. That being said, it can still always be used as a support unit if the breakthrough role isn't working out.

The motorized rocket artillery used by the USSR during WW2 had the nickname of "Katyusha" by the Red Army, in reference of the popular wartime song of the same name. The Germans gave it the nickname of "Stalin's organ" due to the distinct sound that the weapon produced when firing. This sound can be heard in-game if you zoom in on a MRA division that is in combat.

Tanks! If infantry is the foundation for units in HOI4, armored battalions are the steel frames. Tanks are unified not by a shared origin but instead from having a shared set of characteristics. These characteristics also constitute the definition of a breakthrough unit, and each armored battalion can be seen as a variation of this definition.

The characteristics normally present in breakthrough units can be neatly divided between almost universal characteristics and common but not universal characteristics. That being said, this is going by the expectation that we’re talking about normal tank designs. Thanks to the tank designer added in No Step Back, you can design tanks that ignore pretty much everything I am about to say. These designs however tend to be gimmicks, so I won’t account for them unless it is relevant. This also means that this section is pretty reliant on you owning NSB, as I’ll approach all tank units through their NSB iteration. You should still be able to extract some information if you don’t the DLC, but don’t take what I’ll say as fact. You shouldn’t have been doing that anyway. Positive scepticism is important!

Almost universal characteristics among tanks and breakthrough units include high attack stats, high BRK, low DEF, some form of ARM and HARD, terrible ORG, terrible HP, terrible terrain maluses and requiring fuel. Common, but not universal, characteristics include high PC, high SU, great PIER, and good SPD. Tanks specifically are capable of some of the highest values in many of these areas, regardless of whether that is good or bad. Tanks are also uniquely the only type of unit where REL can consistently become problematic.

Breakthrough units are by all accounts glass cannons. They’re big investments capable of major achievements but have many glaring flaws that can make them easily fold under pressure. It’s for this reason that they’re almost always used together with mobile battalions that provide much needed cushioning against said pressure. Unlike other units that require an advantage to push, breakthrough units can create that advantage. If the advantage is already there, then they can capitalize of it much better and cause a lot more damage in the process. You rarely need tanks to win a war in singleplayer. But having tanks lets you win a war quicker, which can be just as important.

Light tanks are very well-suited for the early game, as their low PC, high base SPD and availability from the start makes them require the least investment of any tank. While their biggest flaw of having comparably lacking combat stats is largely irrelevant that early on. Early-game warfare is predominantly infantry based and light tanks have good enough stats to beat any infantry division without anti-armor. Light tanks are similarly good for nations that don’t have the industry or time to invest into other tanks. Despite having the worst combat stats of any main tank unit, light tanks are still tanks. They don’t have the same ability to force advantages but are still very capable of exploiting existing advantages to their full potential. Early-game Italy, Japan, and UK are among the best-suited countries for light tanks, but there are many more good instances if you include ahistorical paths.

That being said, lights falter later on. Their modules are very early-game weighed and stop at 1941. While the modules themselves are stuck to small armaments unless you add a fixed superstructure. The modules of mediums and heavies will catch up to the light by 1940 and then mostly over-shadow it by 1943. The scaling of industries later on will make heavier tanks easier to obtain. And the introduction of infantry anti-armor technologies will make even basic infantry capable of piercing light tanks. Altogether, it becomes hard to justify using lights over mediums or moderns by the late-game. The strongest niche that lights retain by then are support roles where PC is all that matters, or support roles where other tank modules aren’t available. Airborne light armor, light tank recon companies and light flame tank companies are notable examples of this niche.

Light tanks are not the fastest unit in the game, but they are capable of forming the fastest breakthrough divisions that can still put a good fight.

The workhorse of the tank family, medium tanks offer the best balance between potent combat stats and manageable cost/upkeep. With direct access to medium armaments that provide amazing attack for a respectable cost. A good starting BRK, SPD, and REL that makes it arguably the most flexible tank module. Alongside being the cheapest unit with genuinely menacing ARM. There are very few blatant flaws with the medium’s design that are unique to it. Arguably the most significant one being that the medium’s module is the last to be unlocked out of the main three. Taking until 1938 to be unlocked and only getting really good by 1940, making mediums largely unavailable for the early game. It’s also the one tank unit that is easiest to get hubris with. Don’t be a fool and get counter-encircled with a medium. It can happen to anyone.

Mediums tend to be the common tank choice for most major countries. While they are certainly usable by minors, they tend to be just outside the range of affordability unless entirely focused upon. Canada and Hungary are two good examples of a minor that can afford mediums. Mediums are also the first tank that can effectively counter other tanks. As long as you get a turret with good anti-armor, they’ll easily beat most light tanks. Against their own kind, they may need external help to win. If you want a tank to beat all tanks, then you’ll want to look at heavy tanks.


In the first year, in the first battle
When the romans first lengthened, one stood
They chose the path of pepertual torment
In their ravenous momentum, they found no peace
And with burning tracks, they scoured the Derna plains
Seeking vengeance against the soldiers who had wronged them
And those that tasted the bite of their gun named them
The Medium Tank

Heavy tanks are utterly terrifying. Their BRK is among the best in the game. They have access to heavy armaments which sport some of the highest SA, HA, and PIER in the game. Their ARM can become so strong that even dedicated anti-tank can’t pierce it alone and altogether are pretty much unstoppable in ideal conditions. The problem with heavy tanks is that their ideal condition is hard to achieve.

Heavies have ridiculously high PC. So high that only high-industry majors like USSR, Germany and USA can reasonably afford them before late-game. They’re the first tank unit where it can take serious compromise to maintain 100% REL, and their SU is so high that they’re at serious risk any time they lose connection to the supply line. While heavy armaments provide some of the highest attack stats in the game, they’re all so expensive and lopsided that you’re usually better off with a medium armament. Lastly, maintaining high SPD is very difficult without seriously sacrificing REL. Just the module of a heavy tank requires a ton of work to get right, and it only gets worse in action. But the reward for all of this is a tank so strong that pretty much nothing can beat it.

Heavy tanks are very often excessive and almost never needed in favour of other tanks. But there are some roles that heavies are uniquely suited for. Certain positions, like forts, may be so difficult to break that a heavy tank is genuinely required. Certain majors can achieve an industry that is so big by the late-game that the PC of heavy tanks becomes negligible. And their ridiculously high ARM makes them the perfect counter to other tanks if you don’t want to spec into TDs.

There’s also a more nefarious role well-suited to them. Because of how ARM is calculated, you can add a unit with high ARM to a division lacking in it and still get a good final value. Using this with infantry (usually in the form of special forces) is referred to as space marines. It works with both mediums and heavies, but the latter is preferable to minimize the risk of being pierced. There’s more nuance to this, but I’m not very experienced on the topic and can’t provide much more help on it.

Ah, super-heavy tanks. Arguably one of the most infamous niche units in the game and the logical end-state of big tanks. Super-heavies have the best ARM and PIER of any tank, which means they’re the best in the entire game. While they have their own unique armament, its attack stats is generally on-par with that of heavy armaments outside of the PIER. Uniquely, super-heavies are a support company rather than a battalion. This makes them especially well-suited for space marines but can still be put onto regular tank divisions to beef up their stats. There’s only one glaring problem: The PC of super-heavy tanks is the worst of any land unit.

For reference, a basic super-heavy tank costs around 90 PC. Military factories in HOI4 produce 4.5 PC per day if you exclude modifiers from technology, resources, and production efficiency. A single super-heavy tank support company requires 20 super-heavy tanks. This means that, going by default values, it takes 20 days for a military factory to make a single super-heavy tank and 400 days to fill out a single support company. In comparison, it takes roughly 15 days to fill out a single infantry battalion. If heavies are only viable to the industrially strongest countries in the game, then super-heavies are viable to none.

This isn’t even accounting for all the other flaws that super-heavies have. Their SPD and REL are easily among the worst in the game to the point that you’ll rarely get to increase its ARM enough to actually be more than that of heavies. They lack any hardness thanks to being a support company and have outright terrible SU. There are no viable use-cases for super-heavy tanks. They are by all-accounts a joke unit. But by God, are they a good joke.

Arguably the most well-known super-heavy tank in history is the German made and ironically named "Maus". Weighing in at 188 metric tonnes, it is the heaviest armoured fighting vehicle ever built and was so heavy that it couldn't cross most bridges. Instead, it had to be forded or snorkeled over rivers. Despite that, you cannot make super-heavy tanks into amphibious tanks in HOI4.

The protégé of the MBT, modern tanks are a late-game fusion between mediums and heavies. While attack stats are identical due to shared armaments, everything else isn’t. Moderns combine the potent BRK, HARD and ARM of heavies with the SPD and SU of mediums. The only things going against moderns are that their PC and resource demand weighs closer to heavies than mediums and they lack the option of secondary turrets. There is also the most important downside: Modern tanks are only unlocked by 1945.

Modern tanks should by all-accounts be your last pivot in tank design. They are extremely powerful and pretty much better in every way than all the tanks that came before, but they are unlocked so late into the game that the process of swapping to them is their main downside. You’ll usually either be done or close to done by the time you reach 1945. Meaning you only ever really get to see modern tanks being used in ahistorical sessions. Even so, most people will have mentally clocked out by then and be uninterested in switching. If you find yourself in a situation where switching to them is possible, use it. Modern tanks are the pinnacle of breakthrough units in HOI4 and by themselves pretty much perfect. Use the opportunity you have to see them in action. It may take a while to get that opportunity again.

Amphibious tanks, or amphibs, continue the design philosophy of amtracs by giving light tanks the terrain bonuses of marines with slightly worse stats elsewhere to balance it out. They suffer very similar issues as amtracs regarding special forces capacity and the investment required in them, but they are better in combat by merit of being tanks. Of course, you’ll still need to combine amphibs with amtracs to get good amphibious breakthrough divisions. Additionally, amphibs are based off light tanks and thus aren’t particularly amazing as breakthrough units. They excel at doing what marines are meant for: Naval invading and attacking rivers/marshes. Elsewhere, you’re better off with amphibious drive tanks. It also goes without saying that amphibious tanks, like amtracs, requires Man the Guns.

If you own No Step Back alongside Man the Guns, the improved version of amphibs is replaced by a single module: Amphibious Drive. Add it to any of the main three tank modules and you can turn them into amphibious tanks at a cost to BRK, REL, HARD and PC. You also get a slightly better SU, weirdly enough.

Amphibious drive tanks retain the ARM and attack stats of their original design, which makes them much more flexible than pure amphibious tanks. You also have the option between making amphibs out of lights, mediums, or heavies. Amphib lights are basically stronger amphibious tanks, amphib mediums are the most versatile and amphib heavies form the strongest amphibious unit in the game. Amphib mediums and amphib heavies are especially powerful for their ability to transition a successful naval invasion into a land-offensive without pausing to recover or await reinforcements.

The main issues with amphibious drive tanks are that they suffer similar problems to amphibs and amtracs to an exacerbated degree. The amphibious drive is unlocked in 1941 and the units are wholly unique, making them a very high-investment that you can only pivot to well into the game. On-top of that, they are massively handicapped by special forces capacity and technically worse than their non-amphib versions. However, their dual-terrain flexibility makes the investment much less risky compared to amtracs or amphibs. You can use amphib drive tanks like normal tanks without much loss, unlike amtracs or amphibs where you really need to validate the investment.

Although its own category, I’ll discuss every unit together as they all fill a similar niche. Armored Combat Support Battalions are armored versions of combat support battalions. Artillery becomes self-propelled artillery (SPA), anti-tank becomes tank-destroyers (TD), anti-air become self-propelled anti-air (SPAA) and rocket artillery is fused with regular artillery (as SPA can use rocket armaments.)

You usually don’t need to make a tank into SPA/TD to use SPA/TD armaments. For TD armaments, it’s often better to make the tank a TD anyway for the increase in HA and PIER. For SPA armaments, either option is viable. As making the tank a SPA increases SA but also massively increases SU and makes the unit use 3 CW. For SPAA armaments, you don’t have the option. Not like you’d want to stick, since SPAAs get a big decrease in SU.

While all of these can be used as support units like their non-armored versions, they generally don’t provide much difference outside of ARM and having more stats per battalion. This makes their support role best suited for armored divisions as to maintain high average ARM, but they can also be used in non-armored divisions to make space marines. What makes them interesting is that you can still use them like breakthrough divisions. With SPA, you get breakthrough divisions that are insanely strong against infantry but completely fold against armor. With TDs, you get breakthrough divisions that suck against infantry but completely demolish armor. With SPAA, you get basically a support division that does nothing except destroy enemy aircraft and block damage. The main downsides with all of these units is that they’re very high investments with very blatant issues. SPAs sacrifice much needed anti-armor and SU for pure infantry devastation. TDs rely entirely on the enemy having great tanks to be of value and SPAAs are questionable useful given that you can just put the PC into your airforce instead. They can be very fun to use, but are tough sells over the flexibility of normal tanks.

Yes, this is a real tank.[en.wikipedia.org]

Support companies don’t work like any other category. They take up their own unique slots in the division designer, don’t allow replicas in the same division template, don’t contribute CW, usually provide niche bonuses rather than beefing up general stats and have a completely different philosophy for their usage. Since they don’t provide CW and have generally pretty specific uses, the main debate surrounding support companies is whether or not their bonuses are worth the PC and the reduction in any stat that calculates by averages. As such, there is generally little to say for most of them. Which means that it’s time for a lightning round.

Support artilleries are all very similar to their line artillery versions. The major difference being that the support company versions provide roughly 40% less stats while requiring 33% or 66% less equipment. Simply put, they provide less stats but are much easier to invest in.

Support anti-tank and support anti-air largely retain the use-cases of their battalion versions and can easily be added to your divisions if you want a basic counter to armor or CAS. Support artillery acts as a very basic damage buff that is applicable and useful to pretty much any division imaginable, making it arguably the most common support company in the game. Support rocket artillery is largely the same as support artillery but can be used alongside it as a pseudo-replica if you want a further damage boost later into the game. These are among the only support companies that just beef up combat stats and as such are pretty much always useful to have as long as you can afford them.

Engineer Companies focus on alleviating terrain penalties, providing DEF bonuses in certain terrain, improving ENT, and slightly increasing both general DEF and BRK. They’re among the most expensive non-tank support companies but what they provide helps significantly both offensively and defensively. In general, there are very few use cases where it’s better to go without engineer companies.

Engineer companies also have two variants: Pioneers and Jungle Pioneers. Former is locked behind the marine doctrine and requires Arms Against Tyranny while latter is locked behind the Brazilian national focus tree and requires Trial of Allegiance. Pioneers sacrifice most terrain bonuses to focus more on amphibious terrain (which is used in naval invasions) and potentially jungle terrain, while Jungle Pioneers do the same but focus entirely on jungle terrain. Engineer companies are already a must for amphibious divisions, making pioneers a great alternative if you want to focus more on naval invading. Jungle pioneers on the other hand are only really useful in the Tartarus called South America.

Recon Companies primarily provide REC, which makes it easier for generals to get initiative and thus choose combat tactics that disable the enemy’s combat tactic. They also provide SPD bonuses for most terrain and some additional stats depending on the variant, of which there are 6. To quickly break each version down:

• Regular cavalry recon is one of the cheapest support companies in the game.
  
• Motorized is the most versatile recon company.
  
• Armored car provides the highest REC.
  
• Light tank provides the best combat stats and can have its equipment designed to increase other stats like ENT or FC.
  
• Airborne light armor (Yes. This is classified as a recon company.) is the same as the previous but can be parachuted and has much worse stats in every regard.
  
• Rangers provide a wide arrange of different stats and are tied to the mountaineer doctrine
  
• Long range patrol is cavalry recon with much better stats but is exclusive to Finland.

Recon company is kind of hard to discuss as it’s one of the more hotly debated support companies. Plenty of people consider the REC to not be worth the decrease in certain stats as it too heavily relies on external factors to be consistently useful and there are better ways to influence combat tactics. At the same time, this is going by the stats of cavalry recon. One of 7 versions of recon. It’s better to examine the usefulness of recon by your current conditions and said external factors rather than always adding it or always ignoring it. If you want to learn how to design your own divisions then you’ll want to learn how to adapt after circumstance, which this unit excels at teaching.

Military Police (MP) is the first of three support companies with a very similar use-case: An upfront cost that can reduce future costs. In this case, it’s an increase in SUP to minimize the cost of maintaining resistance garrisons. The bonus works by percentage, which means it can actually make the garrison more expensive if it’s too small. Outside of that, it is very simple and straightforward to use. It’s fairly common to make a division template solely for resistance garrisons so that MP isn’t put on divisions meant for combat, as MP is utterly worthless for combat. Even then, MP is one of the cheapest support companies. So you won’t be at a major detriment anyway.

Maintenance Companies increase the average REL of a division and is the only way to increase equipment capture ratio (ECR), which lets you steal a portion of the equipment lost by an enemy division. In practice, they slow the rate of which a division will lose equipment. Their usefulness depends on the average REL and PC of the division. High REL and low PC divisions like infantry are unlikely to be worth the cost, while low REL and high PC divisions like super-heavy tanks practically demand maintenance companies. Keep in mind that REL has no effect over 100%, as this is one of the easiest ways to exceed that limit.

Field Hospitals provide trickleback and decrease exp. loss. In practice, they decreases the rate of which you lose manpower and increase the rate at which divisions gain experience from active combat. Problem with this is that the most manpower-demanding units tend to be the cheapest. Which does not mesh well with field hospitals having among the highest PC of any non-tank support company. Use them for when you have a large industry but a lacking manpower pool. Or when you want to increase a division’s experience as quickly as possible.

Logistics Companies are the only unit capable of reducing SU and FU. Their usefulness entirely depends on the SU and FU of the division, alongside the general availability of supply in the frontline. They’re pretty much worthless on low SU divisions like infantry and rarely useful in high-supply theatres like Western Europe. But for high SU and FU divisions like tanks and in low-supply theatres like Eastern Europe, they can be the determining factor between victory and defeat. Never underestimate the importance of supply.

The variant, Winter Logistics Company, isn’t actually a logistics company variant since it provides entirely different stats and isn’t mutually exclusive. But you likely thought it was, which is why I’m putting it here! It’s another support company exclusive to Finland that provides bonuses for cold acclimatization and fighting in snowy terrain. Obviously meant for the Winter War and Continuation War. The bonuses are pretty niche, but it’s quite cheap and useful in the right conditions.

The definition of an advantage pusher, signal companies provide INIT to increase planning speed, RR and CORD. They’re designed to be used with fast moving breakthrough division that you don’t want bogged down by planning, recovering ORG or by being stuck in a particularly long fight. By themself, signal companies won’t tip the scales of a fight. They're meant to be used on offensive divisions which are expected to win to make sure they keep winning. As such, they have little value on the defence where you want the front to be static and stubborn.

Arguably the only “niche” support company that isn’t locked behind a focus tree or special forces doctrine. Flame tanks are accessible by putting a flamethrower on a tank and then changing the role to flame tank. Sadly, this can only be done on the main three modules. Between the three: Lights are the best for cost, mediums are the best for support and heavies are the best for combat.

Flame tanks provide minor bonuses to attack in most terrain alongside big bonuses to attack in forts and cities. Flame tanks work best with regular tanks as both require fuel and the latter fares pretty badly against forts and cities. It’s a very good idea to use them together with engineer companies to alleviate non-weather terrain penalties as much as possible. Outside of that, flame tanks are pretty difficult to make good use of. The attack stats of the flamethrower are practically non-existent while the other combat stats are massively reduced from their original value. One notable niche use-case for flame tanks is raising ENT and FC through the addition of dozer blades and fuel drums in their design. This can also be done through the armored recon companies, meaning you can stack the two for maximum effect.

This is a bit of a weird unit to end off this entire breakdown. Assault Battalions, as the name implies, are basically just an infantry battalion as a support company. Some of their stats are slightly better than infantry but they require 10 support equipment alongside having ORG and RR akin to other support companies.

To be honest, I don’t know what to say about this unit. It’s just weird and kind of pointless. It fits neither infantry divisions nor breakthrough divisions. It’s also exclusive to Italy, who has no need for a unit like this. I have nothing more to say, so I might as well give some closing notes.

This guide ended up being a much bigger project than I anticipated and definitely took a while to make. It’s an idea that I’ve had in the back of my head for a very long time but one I never found a right moment to make into reality. Turns out there’s a reason no one has bothered to make something of this scale before.

I don’t have any links for me to shill or ways for you to support me if you want to. Spreading word of mouth about this guide is enough to make me satisfied. If you felt like I missed something or messed up somewhere, just make a comment about it and I’ll try my best to respond swiftly. A lot of the information here was gathered from personal experience and hearing from others over the years. Part of the reason I wanted to make this guide for so long was to have an excuse to talk exhaustively about all the arcane knowledge that I’ve accumulated. But I know I’m not omnipotent. In fact, this project took quite a bit out of me because I’m frankly terrible with self-control at times and the final stretch was a lot longer than I originally thought. So I hope you came out of this guide more aware than when you started. That’s all, hope you enjoyed reading this!