Stronghold Category structure
Stronghold
The heart of your empire. Upgrading the Stronghold allows you to build and upgrade other buildings and clears more space for your base.
Max Level25
Base Limit1 buildings
Total Requirements
From level 1 to max level
My Building LevelLevel 0
🏰
Upgrade Time
Single92d 8h 46m
Iron Cost Single23,685,100
Upgrade Progression
Click a level to mark your base progress
StructureLevel 1
Upgrade Cost
TimeInstant
StructureLevel 2
Upgrade Cost 4,900
4,900Time1m
StructureLevel 3
Upgrade Cost 12,300
12,300Time10m
StructureLevel 4
Upgrade Cost 26,600
26,600Time55m
StructureLevel 5
Upgrade Cost 47,700
47,700Time2h 15m
StructureLevel 6
Upgrade Cost 75,600
75,600Time4h 25m
StructureLevel 7
Upgrade Cost 113,000
113,000Time7h 35m
StructureLevel 8
Upgrade Cost 162,000
162,000Time11h 45m
StructureLevel 9
Upgrade Cost 228,000
228,000Time17h 5m
StructureLevel 10
Upgrade Cost 301,000
301,000Time23h 35m
StructureLevel 11
Upgrade Cost 388,000
388,000Time1d 7h
StructureLevel 12
Upgrade Cost 489,000
489,000Time1d 17h
StructureLevel 13
Upgrade Cost 619,000
619,000Time2d 3h
StructureLevel 14
Upgrade Cost 753,000
753,000Time2d 15h
StructureLevel 15
Upgrade Cost 904,000
904,000Time3d 4h
StructureLevel 16
Upgrade Cost 1,073,000
1,073,000Time3d 19h
StructureLevel 17
Upgrade Cost 1,260,000
1,260,000Time4d 12h
StructureLevel 18
Upgrade Cost 1,490,000
1,490,000Time5d 6h
StructureLevel 19
Upgrade Cost 1,719,000
1,719,000Time6d 2h
StructureLevel 20
Upgrade Cost 1,969,000
1,969,000Time7d
StructureLevel 21
Upgrade Cost 2,108,000
2,108,000Time8d 1h
StructureLevel 22
Upgrade Cost 2,367,000
2,367,000Time9d 4h
StructureLevel 23
Upgrade Cost 2,439,000
2,439,000Time10d 9h
StructureLevel 24
Upgrade Cost 2,545,000
2,545,000Time11d 15h
StructureLevel 25
Upgrade Cost 2,591,000
2,591,000Time12d 19h
Strategic Usage
The Stronghold is the cornerstone of your base. Beyond unlocking new building slots, every upgrade increases the maximum potential level of all other structures. Prioritize this whenever possible to maintain progress speed.
Efficiency Tip Always try to synchronize your upgrades. Start long-duration upgrades (like Stronghold or Advanced Storages) before long sleep periods or work shifts.
Storage Priority Never let your Storages overflow. If your resources hit the cap, your Mines and Farms effectively shut down, wasting valuable production time.