How Is Aggressive Expansion Calculated?

[vonlinchen]

Playing as Brandenburg, I annexed pomerania, in the peace menu it said I would get 23 AE for annexing them.

I annexed them but Austria's relations are now declineing with me due to 39 AE.
Bohemia has 45 AE against me.


Is the AE in the peace menu just meaningless?

 

[dezuman]

The base AE is multiplied by a bunch of factors for each country, there's a sidebar that lists what they'll get.

 

[Denkt]

From eu4 wiki

The degree to which any particular country is affected by aggressive expansion depends on the following:

Direct victims of the aggressive act will have a stronger reaction, receiving twice the final aggressive expansion modifier. The modifier is rounded down to the nearest integer for each act before being summed up.
Allies and subjects of the aggressor will be significantly less affected by aggressive expansion.
Distance between site of aggressive expansion and border of a nation.
Example: France taking Roussillon is more distressing to Castille than France taking Franche-Comté.
Regions and continents: Taking land in a particular region or continent will provide a larger penalty towards other nations in the same region or continent.
Example: Castile can conquer provinces in North Africa / Africa from Morocco without incurring significant aggressive expansion modifiers with Portugal or Aragon due to them residing in Iberia / Europe.
Size of aggressor: A big country will suffer bigger aggressive expansion (so a nation holding over 300 provinces might force its neighbours into a big coalition with the annexation of one single province while a minor might annex another minor and only suffer 1 or 2 points of aggressive expansion for it). Another explanation would be the relative strength or relative size of the annexing country and the country that is upset by that action.

 

[ikkiks]

That's base AE, there's a couple modifiers for that depending on many factors, like HRE, religion and region. Hover your mouse over the base AE in the peace menu to see how much each nation will get.

 

[Frungy78]

Annexing/vassalizing within the HRE is a big no-no. Be a huge nation so you don't care, take small bites, or butter up all the neighbors so they don't join a coalition.