Whenever you upgrade your City-State to a Civilization your towns will start to generate daily upkeep which has to be paid off.
Upkeep is important for your town to keep all your buildings and claimed plots maintained and secured.
You receive upkeep from maintaining built structures in your town, having claimed outposts (requires Government Mercantilism) and by having spread upkeep. More is explained below
The town level of your town generates some upkeep since you have more potential tiles to maintain.
Below is a table with which town level creates how much upkeep.
| Town Level | Upkeep |
|---|---|
| Settlement | 500 coins |
| Hamlet | 750 coins |
| Village | 1 250 coins |
| Large Village | 2 000 coins |
| Town | 3 500 coins |
| Large Town | 5 500 coins |
| City | 7 000 coins |
| Large City | 8 000 coins |
| Metropolis | 10 000 coins |
| Capital | 15 000 coins |
Building structures in your town is very beneficial since it can provide some buffs and efficiency to your town. Every structure you build will have an amount of upkeep to maintain.
The amount differs per building and can be found on the page of the structure on this wikipedia.
Whenever you claim an outpost chunk for your Town using the Mercantilism Government you receive 5 000 coins upkeep for every outpost claimed by your town. It is very effective to keep your outposts to a minimum since claiming too much might bring too much upkeep to your town and this will result into great debt.
Whenever you start claiming, it might result into some spread upkeep since it will take some effort to reach the claimed plot. Outpost chunks are not taken into account this way.
This is calculated in chunks. There is a grace distance of 8 chunks from the founding chunk of your Capitol / Town Hall.
Spread upkeep is calculated with this formula;
10 * (distance - grace distance)^1.5
If you don't pay your bills in time your town or Civilization can fall into ruins.
If you don't pay your bills within 14 days, people can start buying your Town or Civilization. If no one does that and your town is still in debt by the 21th day, it will fall into ruins.
City-States cannot buy other towns or city-states, and Civilizations cannot buy other small Civilizations (lower than 25% of their current score)