War exhaustion is a number that models how unhappy the people in a country are because of its wars. The primary effect of war exhaustion is as a cause of rebellions. The causes of war exhaustion are recruiting troops, and being at war. War exhaustion is often abbreviated as WE by players. In this article we write out "war exhaustion" when referring to the general concept, whereas we use "WE" to refer specifically to the number the program is using.
Domains of War Exhaustion
War exhaustion affects both a country as a whole, and each city controlled by that country. The size of the effect on cities is a function of the country's WE, and thus we refer to the country's WE level, before rounding, as the "base" WE, or BWE.
Seeing War Exhaustion
Internally, BWE is kept as a floating number, though it is not shown in-game anywhere. You can see the exact number by inspecting a save file. This number is always truncated before being used for an in-game effect.
In-game, if you are at less than maximum stability, you can see your own country's war exhaustion in-game by going into the tech screen and hovering over the stability slider. If you've got nonzero WE, you'll see that it appears as a malus to your stability investment. You can also see a city's modified WE (see below) by examining the city's revolt risk breakdown on the tooltip.
Effects of War Exhaustion
On a country, war exhaustion works as a malus to stability investment.
In each city, the controlling country's war exhaustion increases the city's revolt risk. If this results in an increase in net revolt risk, the effect is to decrease its province taxes. This, in turn, may reduce the city's recruitment capacity for both land and naval units.
Depending on the relationship of the country and a particular city, the effect of war exhaustion may be amplified. The effective WE in a city may be greater than the BWE. (It is never less, except insofar as trading posts and colonies are not affected by war exhaustion.) There are three aspects of the relationship of a city to its controlling country that may amplify its war exhaustion: whether it is a core or not, religion, and culture.
There are four cases. In all cases, the computation of per-city war exhaustion is performed as follows: first, the BWE for the controlling (not owning) country is taken and truncated, yielding an integer. Then the integer is multiplied by a war exhaustion multiplier, as listed below. Finally, that number is also truncated, resulting in the city's WE.
The war exhaustion multipliers per city, and conditions for them relative to the controlling country, are as follows.
- 1.0, if the city is on a core province, regardless of religion and culture.
- 1.25, if the city has the state religion and a state culture
- 1.5, if the city has the state religion or a state culture, but not both
- 2.0, for other cities (wrong-culture and wrong-religion)
For example, a country has BWE of 3.783. In each of its core provinces, city WE is 3. In cities which match the state religion and culture, city WE is also 3. (3.783 rounds down to 3.0; then multiplied by 1.25, which is 3.75, then rounded down again.) In cities with one, but not both, of the state religion and culture, city WE is 4. And finally in wrong-culture wrong-religion cities, city WE is 6.
When a country is bankrupt, double WE applies to cities. You'll see the war exhaustion line twice in the list of factors.
Changes to Base War Exhaustion
War exhaustion increases immediately when a country recruits armies or imposes war taxes. It also changes monthly, increasing after "active" warfare months, and decreasing after "inactive" months or when at peace.
Immediate Increases of BWE
When a country recruits armies, regardless of if it is at war or not, its war exhaustion increases. Each army unit (1000 infantry or cavalry, or 10 artillery) recruited immediately increases the BWE by 2.0, divided by the country's manpower pool maximum. In other words, your BWE increases by 1.0 if you build as many land units as half your "Maximum Manpower" value.
When a country imposes war taxes, its BWE immediately increases by 1.0.
Monthly Increases to BWE
The other changes to war exhaustion do not happen immediately based on a country's actions, but rather, are adjustments made at the end of each month based on what happened in that month.
Things that are not "active" war include:
Monthly Decreases to BWE
War exhaustion can also decrease at month's end, if the country is at peace or is "inactive" in war. When a country is at peace, its BWE drops by 0.25 each month (3 per year!). If it is at war, but inactive, its BWE drops by 0.0125 (0.15 per year).
There is a maximum for how high BWE can get. The basic maximum value for the BWE is 10, however, two domestic policies affect this maximum. The innovative and centralization sliders each affect it, by -2 to +2 as they range from 0 to 10. Thus a fully decentralized and intolerant policy will yield a maximum BWE of just 6.
A country's BWE is truncated to its maximum value at each month end when it is recomputed. You will see higher WE values during a month of heavy recruiting, but they will be truncated before they cause any harm.
War Exhaustion and AIs
Generally, AIs suffer far less from war exhaustion than players do. AI countries have their WE and its effects reduced, except on Very Easy where they have the same WE effects as a human. AIs at Easy-Hard have their WE and maximum WE halved. On Very Hard, their WE and max WE are divided by 3. Thus their highest possible maximum WE at Very Hard is 4 (for a centralized and innovative AI - very rare). Most Very Hard AIs will have effective max WE of 2, since the AIs tend to be decentralized and closeminded.