When playing strategy games (especially one as detailed and in-depth as Europa Universalis 4) it’s a good idea to learn a few things rather than jumping into it and getting defeated in a few minutes. Unit Composition is important in EU4, and this info should help you get better at the game. This is our Unit Composition Guide for EU4.
Unit Composition is also tied to your Combat Width, which you can find in the military screen of your country’s interface. Your Combat Width determines how many regiments can fight at once. You can increase this by unlocking Military Technology.
Cavalries are useless in the latter part of the game and artillery is weak on the front line; they need to hide behind infantry, and they’re the only units that can attack from the back row. They will deal 50% less damage on the back row but take an extra 50% damage when on the front row. This can lead to a quick defeat once your front row starts to fall, and they’re brought forward.
Cavalries are probably the most overused and overpriced unit at 2.5x more expensive than infantry. The good thing with cavalry is they can attack the flanks of the enemy. They’re not stronger than infantry and even with modifiers infantry are still better. Do you think they should have such a high price tag?
When starting out you should still use cavalry but it’s best to ditch them at around Tech 10. Put your artillery at the back and infantry on the front row. A full Combat Width cavalry is useful for a short time during the early stages of the game but once the units on the flanks are defeated that cavalry will be left out and won’t be used. If you have a cavalry focused nation, they have more bonuses for those units and cavalry are far more useful later in the game.
When in combat your units are reinforced by the back row, so if your Combat Width is 16 and you have 20 thousand soldiers ready for battle 4 thousand will be in the back row. When a unit ahead of them dies the reserves move forward to replace them. When you get Tech 5 update your Military Template to the 24,4,0 template now that your Combat Width has increased. You can change to this and any others by going to Conform to Template.
The Shock Damage cavalry does is superior to infantry, and they deal good flanking damage. A decent composition at the start of the game is 12 infantry, 4 cavalries and 0 artillery. All battles go through 3 phases alternating between Fire and Shock. Fire Phase is first which represents ranged attacks such as longbow, artillery, muskets going first. The shock Phase is next which is hand to hand combat, these battle phases will continue until one side has no more moral and they retreat.
An ideal Army Composition is to have all infantry at the start of the game since cavalry costs a lot. The first round of artillery you unlock they’re not very good but are useful and when sieging they’ve extremely useful. Keep up to date with your Military Templates and bring multiple of your armies together (stacking) to create a larger force but by doing so you will get more attrition. By splitting the army before and after a fight you will get less attrition. And no one wants that to be high. And that ladies and gentlemen is my EU4 Army Composition guide.