Your first battle: count the troops before you commit

By Chenyjunny · Rules reviewed October 19, 2026

For a walkthrough with screenshots, start with an actual opening. This page uses a constructed situation to calculate the troops needed for a battle.

Era of Conquest rewards choosing a fight you can hold after winning. A large number on your border does not tell the whole story: the origin keeps one troop, the defender gains a bonus, sea crossings reduce your force, and repeated attacks add fatigue. This guide works through a constructed border situation using the game's rules. It is a calculation example, not a report of a completed match.

Start with one decision

Choose a scenario, a nation, and an objective on the title screen. For a shorter campaign, select the 30-turn objective. Select one of your provinces, then an adjacent target. If another nation owns the target, you must be at war before attacking; neutral land does not require a declaration. Check the attack menu before confirming.

For this example, the target holds 7 troops, production 5, fortification 2, and era 1. Its defence bonus is ceil(5 / 2) + 2 + 1 = 6. The total to beat is therefore 13. Equal force fails. You need at least 14 effective attackers.

How many do you actually send?

On land, sending 14 is enough in this example if the origin has no fatigue. Across water, sending 21 gives only 13 effective troops and fails. Sending 22 gives 14 and succeeds. Since the origin always retains one, its displayed army must be at least 15 for the land attack or 23 for the sea attack.

The following table gives the minimum number sent against that same total defence of 13. Add one to find the minimum army needed at the origin. These values include the game's rounding, so they are more useful than estimating a percentage in your head.

The order matters: across water, round sent × 0.6 up first. Then multiply by 1 − 0.1 × fatigue and round down, with a minimum effective force of 1. Compare the result to the defender's total. For example, 32 sent across water becomes 20, then 14 at fatigue 3; 31 becomes 19, then 13, which fails.

Winning the attack is only half the decision

A minimum-force victory leaves a single troop at the target. The captured province has already used its action for the turn. Before committing, inspect the enemy provinces around the target and your own remaining actions. A narrow win beside a stronger enemy may be a poor trade; waiting, reinforcing another origin, or securing another border through diplomacy can be better. The opponent's next move is not guaranteed.

Fatigue increases after an attack. With no rest, the first attack uses 100%, the second 90%, the third 80%, and the fourth 70%. A turn without attacking removes one fatigue stack. Moving to a different origin can avoid using an exhausted army, but check that province's own fatigue rather than assuming it is fresh.

Decide what the next turn is for

With 6 gold, Levy adds 4 troops immediately and uses the province's action. Develop also costs 6 gold and adds 1 production, helping later turns. Fortify costs 4 gold and adds 1 defence. Choose the action that answers the threat in front of you: immediate troops for a dangerous border, production for a province you expect to keep, or fortification where a neighbour could attack. Each choice prevents another action from that province during the same turn.

Do not treat expansion as free income. Once you own more than 12 provinces, administrative efficiency falls until it reaches 0.5 at 24 provinces. Production, per-province rounding, difficulty, and economy settings affect the actual return. See the combat and economy guide for the limits and costs, and the diplomacy guide for avoiding simultaneous wars.

Before pressing End turn

1. Check which provinces still have an action.
2. Check the troops left at both the origin and target.
3. Check exposed borders and current wars.
4. Keep your objective in mind: more land, surviving to turn 30, and advancing an era call for different spending.

The numerical examples use the current combat rules. They do not predict AI decisions or promise a win. If an example differs from your game, email [email protected] with the scenario, difficulty, troop counts, fatigue, and a screenshot.