Upkeep is the you need to pay each hour for your military staff. When all units are stationed in your cities, you can sum up these value yourself by multiplying the number of each unit that has upkeep you have by the upkeep per hour that is indicated in your barracks, and the upkeep bonuses you have researched for that unit type. There are several researches you can acquire via the academy that will reduce your upkeep costs.
- Upkeep is deducted from your account every one hour.
Researches that reduce unit upkeep costs
- Maps ( 2% reduction )
- Code of Honor ( 4% reduction, 6% total )
- Logistics ( 8% reduction, 14% total )
- Militaristic Futures ( 2% reduction per level )
Researches that reduce ship upkeep costs
- Ship Maintenance ( 2% reduction )
- Pitch ( 4% reduction, 6% total )
- Sea Charts ( 8% reduction, 14% total )
- Seafaring Futures ( 2% reduction per level )
Researches that reduce Scientists upkeep costs
If you have several colonies, the amount of upkeep shown in the income overview is divided between your towns dependent on the percentages of the total amount of citizens per town you have, not on the amount of stationed troops and ships. As cities don't have their own gold reserves and all costs are paid out of your gold coffer, this of course only makes your bookkeeping harder to read, rather than offering any insights into your real costs per city.