Division building

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This article is focused on choosing composition of divisions. For a more brigade-oriented view, see land unit selection.

A division is defined as any unit with at least two brigades. A division can contain up to four brigades, or five if the Superior Firepower Doctrine tech is researched.

Divisions can be split and merged in any way needed, and can be broken into individual brigades. There are four basic division sizes:

  • Binary: Two brigades in the division.
  • Triangle: Three brigades in the division.
  • Square: Four brigades in the division.
  • Superior Firepower: Five brigades in the division.

Note that the terms "division" and "brigade" are never exact terms: many militaries had different definitions for these, so the game is not perfectly "historically accurate". Battalions are modeled in the game, to some degree, even though they are called brigades. For example, an Artillery "brigade" only has 1,000 men, unlike an infantry brigade that has 3,000 men. While the game is not a perfect representation of history, the brigade system is a significant historical improvement over Hearts of Iron 2.

Combat and Support Brigades

Brigades can be divided into two types, combat and support.

Combat Brigades

Combat brigades have 3,000 strength and take up space on the front. Usually, a division should only have one type of combat brigade to prevent the different strengths and weaknesses of different unit types from interfering with each other—for example, a slow brigade will hold back a fast brigade, and some brigades have severe penalties in bad terrain that can prevent other brigades in the division from performing well.

The major exception to this rule is the combined arms bonus. This bonus is achieved by combining soft and hard units so that the division softness is between 33% and 66%. Militia is another exception, as it can be effectively mixed with any other non-mobile brigade type to serve as cannon fodder.

Support Brigades

Support brigades have only 1,000 strength but have zero combat width. Apart from this, support brigades tend to have similar cost to combat brigades of similar statistics.

The lower strength of support brigades makes them less durable than combat brigades; however, as they do not take up frontage, more of them can be involved in a combat at a time.

Division Size

There are different motivating factors for considering the most appropriate division size.

Combat Width

In combat, divisions pile in as long as the total combat width is less than or equal to the available frontage. With enough divisions, this will result in more combat width than the listed frontage.

To pack in more firepower within a limited frontage, you can include support brigades, which have the advantage of having no combat width. However, they are also much less durable than combat brigades, so use them only when you need the extra concentration of force.

Frontage is a basic 10, plus an additional 5 per additional direction of attack beyond the first.

Maximum number of divisions on front line

Combat Width 10 Frontage 15 Frontage 20 Frontage
2 6 8 11
3 4 6 7
4 3 4 6
5 3 4 5

Maximum number of combat brigades on front line

Combat Width 10 Frontage 15 Frontage 20 Frontage
2 12 16 22
3 12 18 21
4 12 16 24
5 15 20 25

Maximum number of support brigades on front line (with Superior Firepower)

Combat Width 10 Frontage 15 Frontage 20 Frontage
2 18 24 33
3 8 12 14
4 3 4 6
5 0 0 0

Stacking Penalty

The stacking penalty depends on the number of divisions (NOT brigades as stated in the manual) involved in the combat. It does not kick in until 5 divisions at which point it is ~5%. A reasonable rule of thumb for >4 divisions is that the penalty is ~5% per additional division, although the real number is less than that (actual penalty = 1 - 0.95#_Div - 4).

To fit in the most firepower with the least number of divisions, you will need to make your divisions as large as possible and use heavier units, such as Armour. This is expensive, but again, sometimes you will need the extra concentration of force.


The more divisions you have, the more leaders you can potentially have in battle gaining experience. On the other hand, you will need more commanders to lead them, some of which will be not as good (and, if you have enough divisions, some will have to go leaderless). Furthermore, you will need more HQs, with their associated commander and officer requirements.

Tactical Flexibility

Given a certain number of brigades, you can have a large number of small divisions, or a smaller number of larger divisions. The former will allow you to divide your forces between provinces more finely, which can be useful if you are covering a large area of ground or trying to encircle the enemy. However, you must balance this against the other considerations here.

Division Speed

Since divisions travel at the speed of the slowest unit, it makes sense to try to make all the brigades in a division travel at the same speed.

Skipping Armour Upgrades

It is possible to increase the speed of armour much more quickly by skipping armour upgrades.

Advantages of doing so:

  • Faster armour, with slightly less construction, supply, and fuel costs.
  • One less tech to research per cycle.

Disadvantages of doing so:

  • No Defensiveness increases. In the long run this will make them twice as vulnerable on the defensive.
  • Less Toughness decreases.
  • No Softness decreases (for units that use them). This may not be critical for CA divisions, and can even be a drawback if the decreased softness pushes a division design below the minimum softness limit.

Skipping Engine Upgrades

Conversely, one can skip engine upgrades where unnecessary in order to preserve the Toughness of units.

Advantages of doing so:

  • Slightly higher Toughness, with slightly less construction, supply, and fuel costs.
  • One less tech to research per cycle.

Disadvantages of doing so:

  • Slower.

Hybrid Approach

Between these two lies the hybrid approach, where one skips Armour or Engine upgrades until the brigade type's speed reaches a desired value, then upgrades as necessary to keep that speed. For example, one could increase Armour's speed to 8 to match Engineers by skipping armour upgrades, then keep the speed constant.

Speed Examples

  • Speed Per Upgrade is based on the standard upgrade cycle of 2 years.
Name 1936 Speed Speed Per Upgrade Toughness Per Upgrade
HQ 4 0.5 1
Engineer 8 0 0
Armored Car (no armour upgrades) 9.4 0.2 0.4
Armored Car 9.3 0.13 0.53
Motorized (2 armour upgrades) 8.2 0.2 0.6
Motorized 8.2 0.1 0.6
Mechanized (2 armour upgrades) 9.4 0.4 0.7
Mechanized 9.4 0.2 0.8
Light Armour (2 armour upgrades) 9 0.9 0.6
Light Armour 9 0.5 0.9
Armour (no armour upgrades) 6.75 0.75 0.5
Armour 6.5 0.5 1
Armour (no engine upgrades) 5.5 -0.5 1.4
Heavy Armour 5 0.2 0.6
Heavy Armour (no engine upgrades) 5 -0.5 0.9
Tank Destroyer (no engine upgrades) 7 1 0.1
Tank Destroyer 6.5 0.25 0.3
SP Artillery (no armour upgrades) 8 1 0.2
SP Artillery 7.5 0.5 0.4
SP Rct Artillery(no armour upgrades) 9 1 0.3
SP Rct Artillery 8.5 0.5 0.5

Combined Arms

In v4.02, To get CA you must now build units as follows. They must have 1 infantry type: (Infantry, Calvary, Motorized, Mechanized) and any one of the other type to get the minimum CA bonus. Example 3 INF + 1 ART will get you a 5% CA bonus now.

Given that most(and arguably the best) hard units are also fast, it makes sense to group them with fast soft units so as to take advantage of the Combined Arms bonus. The choices here are Engineers, Motorized, Mechanized, Armored Car, Self-Propelled Artillery (normal or Rocket), and questionably HQ.

The Combined Arms bonus starts at 20% better effectiveness for a CA division. A Panzer (v4.02 Now called Battle Master) trait division leader adds 10% and a Land Doctrine tech adds another 10%, netting 40% better effectiveness. You can also pick up some additional benefits from the HQ structure.

You can have up to 20 brigades without stacking penalty (4 divisions with 5 brigades each). Beyond this, the extra efficiency of using extra support brigades instead of using heavier combat brigades is probably not worth the extra stacking penalty—it would have to be at least 20% more efficient than using heavier combat brigades to be worth it, not to mention the higher supply/fuel consumption.

With a standard 10 width front, the easiest way to achieve 20 brigades on the front is 4 divisions with 3 combat and 2 support brigades each.

As such, depending on your IC / manpower ratio, the optimums would probably be something like:

  • Mot x 3 / TD x 2
  • Mec x 3 / SP Art / TD
  • Arm x 3 / SP Art or Eng x 2 (NOTE: V4.02, This is no longer a CA type division. Must have one of the following in the division: Infantry, Motorized, Mechanized)

The last is probably the most research-efficient: given that SP Art and TD rely on tank techs, you need Arm to give you the appropriate practical. It also avoids AT gun techs if you don't use AT brigades either.

For the slower hard units (Heavy Armour, Tank Destroyers if you concentrated more highly on armour upgrades), Infantry is a natural choice for Combined Arms. Given the high cost of these units relative to Infantry, you'll probably want to be near the softer side of the range.


Depending on what brigade types you select, a division will play one of several roles. You will have to determine the balance of roles of your divisions, given your limited construction and supply capabilities. For example, you will probably need to choose between giving line divisions artillery support, and forming elite breakthrough divisions. Some of this will depend on your playing style—do you prefer to push evenly on all sides, approach from unexpected directions with special forces, or hold the line while your elite breakthrough divisions surround and crush the enemy piecemeal?

Some roles tend to be more expensive than others. In roughly ascending order of cost:


Line units consist of relatively cheap foot infantry—Infantry, Militia, or Garrison. Though slow and not terribly powerful, they are cheap enough to form the bulk of an army, guard static objectives, and so forth.

Rough cost relative to line per combat width: x1


  • Inf x 3-4, a standard triangular or square infantry division.
  • Mil x 5, Militia swarm using Superior Firepower.
  • Inf x 3 / Eng x 1, good for holding fortified lines, but more expensive than regular Inf.

Line + Artillery

Artillery is a good way of giving your line units a little more punch. While it doesn't help your speed any, it gives you an advantage in a broad attack.

Rough cost relative to line per combat width: x1.3 - x2


  • Inf x 3-4 / Art or R Art x 1-2, the standard infantry division with artillery support.

Special Forces

Mountaineer, Marine, or Paratrooper divisions, generally consisting of only one type of brigade in order to avoid diluting terrain bonuses or losing paradrop capability. Though quite a bit more expensive than line divisions, they provide capabilities in terrain most units have trouble operating in.

Rough cost relative to line per combat width: x2 - x3


  • Mtn x 4
  • Mar x 4, a Marine landing force.
  • Par x 4, a large Paratrooper division. Once Airborne Warfare Equipement and at least one level of Cargo Hold is researched, a single Transport Plane can carry four Paratrooper brigades.


Speed, speed, speed. Only average in combat, but good at grabbing provinces before your enemy can react. On the cheaper side, one can go with pure Motorized or Mechanized; when cost is of less concern, Light Armour with Self-Propelled Artillery is the fastest choice here, especially if you skip armour upgrades.

Rough cost relative to line per combat width: x3 - x8


  • Mot x 4, a relatively cheap force with good speed.
  • L Arm x 1 / Mot x1, a force that takes advantage of L-Arm upgrades also applying to Mot, useful in vast, hard to supply areas.
  • L Arm x 3 / SP R Art x 2, fastest division in the game, especially if you skip armour upgrades.
  • L Arm x 1 / SP (R) Art x 4, same speed as the above, but with greater firepower (especially against soft units), and more vulnerable if outgunned.

Heavy Line

Infantry or Artillery backed with slow armoured units such as Heavy Armour or Tank Destroyers to grant a Combined Arms bonus. Expensive and not terribly fast, but hard to stop or dislodge.

Rough cost relative to line per combat width: x3 - x12


  • Inf x 3 / 2 x TD, Infantry with enough Tank Destroyers to get the Combined Arms bonus.
  • Inf x 3 / 2 x SH, Infantry with super-heavy armor for the Combined Arms bonus, and spending extra IC/research to save on manpower.
  • H Arm x 3 / 2 x R Art, Heavy Armor backed with Rocket Artillery. Definitely on the more expensive side. (High Fuel Consumption)


Generally almost as fast as exploitation units, but also boasting the heaviest firepower, breakthrough divisions are expensive and deadly. Ranging from Motorized with enough fast Tank Destroyers to have a Combined Arms bonus, to Armour with Self-Propelled Artillery or Engineers, only a prompt, determined response or bad terrain can stop these divisions.

Rough cost relative to line per combat width: x4 - x10


  • Mot x 3 / TD x 2, Motorized with TD to give a Combined Arms bonus.
  • Arm x 3 / Eng x 2, Armour with Engineers to make them more versatile.

Further reading

Quantitative Division Design

Excel-based Division Design Tool (including tech effects)