Stability is a measure of the nation's internal peace. Unstable nations are more likely to face revolts and turmoil, while stable nations enjoy increased prosperity.
Like many other game mechanics, a player spends monarch power to increase stability, in this case administrative power (). Since these are also the points that go towards increasing the number of ideas and development, it is less likely that a country will always be at peak stability since a player may plan on investing monarch power in other things.
However, due to diminishing returns, it is not recommended to increase stability to more than +1, since administrative points are quite valuable and the player might need them elsewhere.
Effects of positive stability
For each additional level of positive stability, a country benefits from:
Effects of negative stability
For each additional level of negative stability, a country is hit by:
|−1%||Global trade power|
|−5%||Foreign spy detection|
|+0.05||Militarization of state|
Additionally, a nation at -3 stability cannot declare war, and must accept any offered peace deal that is 30% or more below the current warscore.
The base price for increasing stability is 100 administrative power, but overextension and lack of religious unity can increase this cost significantly. Some ideas and advisors decrease this. There are also events and other random factors also modifying the price temporarily. Stability cannot go higher than 3; any events that increase stability at this maximum will not increase stability further.
The base cost for increasing stability is 100 administrative power. The main modifiers affect the cost of raising stability are:
- +50% increase per point of positive stability.
- +50% if another country has sown discontent in the country.
- + (Overextension / 2)%. Half of overextension is added to the cost.
- +(100 - religious unity)%. The lack of religious unity is added to the cost.
- +(100 ÷ republican tradition)%
- A country will have increased stability cost if suffering a disaster.
Reducing stability cost
- Artist advisor: -10%
- Being a Lucky Nation: -10%
- Various decisions, like Unify Islam.
- Oligarchic Republic government: -5%
- Bureaucratic Despotism government: -20%
- Tribal Democracy government: -33%
- Tribal Kingdom government: -15%
- Native Council government: -33%
- Siberian Clan Council government: -33%
- American Republic government: -10%
- Orthodox religion: -10%
- Curia controller: -10%
- Fraticelli religion -5% (only exists in saves imported from CK2)
- Cathar religion -5% (only exists in saves imported from CK2)
- Loyal Clergy: -2.5% to -10%
- The following national ideas decrease stability cost: