Each upgrade increases construction speed by 10%
| Levels | Reduction % | Research Times | Cost | Requires |
| 1 | 9.09% | 29m 36s | 5,000 Gold; 2,000 Metals; 2,000 Lumber | SC 5 Woodcraft 5 |
| 2 | 16.67% | 59m 56s | 10,000 Gold, 4,000 Metals; 4,000 Lumber | |
| 3 | 23.08% | 2hrs 1m 22s | 20,000 Gold; 8,000 Metals; 8,000 Lumber | |
| 4 | 28.57% | 4h 5m 47s | 40,000 Gold; 16,000 Metals; 16,000 Lumber | |
| 5 | 33.33% | 8h 17m 43s | 80,000 Gold; 32,000 Metals; 32,000 Lumber | |
| 6 | 37.50% | 16h 47m 53s | 160,000 Gold; 64,000 Metals; 64,000 Lumber | SC = Level Woodcraft 5 |
| 7 | 41.18% | 1d 10h 0m 59s | 320,000 Gold; 128,000 Metals; 128,000 Lumber | |
| 8 | 44.44% | 2d 20h 53m 0s | 640,000 Gold; 256,000 Metals; 256,000 Lumber | |
| 9 | 47.38% | 5d 6h 17m 36s | 1,280,000 Gold; 512,000 Metals; 512,000 Lumber | |
| 10 | 50.00% | 5d 6h 17m 36s | 2,560,000 Gold; 1,024,000 Metals; 1,024,000 Lumber | |
| 11 | 52.38% | 5d 6h 17m 36s | 2,560,000 Gold; 1,024,000 Metals; 1,024,000 Lumber | SC 11 Woodcraft 10 |
| 12 | 54.55% | 5d 6h 17m 36s | 2,560,000 Gold; 1,024,000 Metals; 1,024,000 Lumber | SC 12 Woodcraft 10 |
| 13 | 56.52% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 13 Woodcraft 13 |
| 14 | 58.33% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 14 Woodcraft 14 |
| 15 | 60% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 15 Woodcraft 15 |
| 16 | 61.54% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 16 Woodcraft 16 |
| 17 | 62.96% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 17 Woodcraft 17 |
| 18 | 64.29% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 18 Woodcraft 18 |
| 19 | 65.52% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 19 Woodcraft 19 |
| 20 | 66.67% | 5d 6h 17m 36s | 3,200,000 Gold; 1,280,000 Metals; 1,280,000 Lumber | SC 20 Woodcraft 20 |
The equation for adjusted construction time given any research level is
AdjustedTime=BaseTime/(1+0.1*ResearchLevel)
or more simply
A=B/(1+0.1*RL).
The time displayed on a building before you upgrade is the time it takes for you to upgrade with your levitation, not the base time. This wiki shows base time on buildings.