Updated for Town Hall 18 (October 2026).
The Star Laboratory is where you upgrade troops in the Builder Base. It is repaired for free when you reach Builder Hall 2, goes up to level 10 at Builder Hall 10, and each level opens two more troop levels, up to troop level 20. All Star Laboratory research costs Builder Elixir.
What the Star Laboratory does
It works like the Home Village Laboratory, minus spells, since the Builder Base has none. Research can raise a troop’s hitpoints and damage, make its ability stronger, or fit more of that troop into one Army Camp slot, depending on the troop.
You can upgrade the lab building while a research is running. The research keeps going, but the new troop levels that the lab upgrade opens only show up once the building is finished. Upgrading the building itself needs a free Builder Base Builder.
The lab is a 4×4 building, bigger than most Builder Base buildings, and you only ever get one. From Builder Hall 6 onward it has to sit in Stage 1 of your base.
Star Laboratory levels
Each lab level needs the Builder Hall of the same number, except level 1, which comes free with Builder Hall 2. The last column is the highest troop level that lab level allows.
| Lab level | Builder Hall needed | Hitpoints | Upgrade cost (Builder Elixir) | Upgrade time | Max troop level |
|---|---|---|---|---|---|
| 1 | 2 | 650 | Free repair | – | 2 |
| 2 | 2 | 800 | 15,000 | 10m | 4 |
| 3 | 3 | 975 | 50,000 | 30m | 6 |
| 4 | 4 | 1,150 | 300,000 | 8h | 8 |
| 5 | 5 | 1,350 | 700,000 | 12h | 10 |
| 6 | 6 | 1,600 | 1,000,000 | 2d | 12 |
| 7 | 7 | 1,850 | 2,000,000 | 4d | 14 |
| 8 | 8 | 2,150 | 3,000,000 | 6d | 16 |
| 9 | 9 | 2,450 | 4,000,000 | 8d | 18 |
| 10 | 10 | 2,750 | 5,000,000 | 10d | 20 |
Where each troop starts
Since Builder Base 2.0, a troop you unlock in the Builder Barracks skips straight to a minimum level that matches your Builder Hall. That means the first research for a late troop is already a high level with a high price.
| Troop | Builder Hall to unlock | Starts at level | First research needs Star Lab |
|---|---|---|---|
| Raged Barbarian | 2 | 1 | 1 |
| Sneaky Archer | 2 | 1 | 1 |
| Boxer Giant | 3 | 3 | 3 |
| Beta Minion | 3 | 3 | 3 |
| Bomber | 4 | 5 | 4 |
| Baby Dragon | 4 | 5 | 4 |
| Cannon Cart | 5 | 7 | 5 |
| Night Witch | 6 | 9 | 6 |
| Drop Ship | 7 | 11 | 7 |
| Power P.E.K.K.A | 8 | 13 | 8 |
| Hog Glider | 9 | 15 | 9 |
| Electrofire Wizard | 10 | 17 | 10 |
Research prices climb steeply with level. For example, the jump from level 19 to 20 costs between 5.2 and 5.8 million Builder Elixir and takes 6 days 12 hours for every troop that can reach it.
What to research first
- Upgrade the lab as soon as you move up a Builder Hall. Every new lab level opens two levels for every troop, and the lab upgrade time is the bottleneck at the top.
- Pour research into the troops you actually fill slots with. Since each Army Camp slot holds one troop type, a single well-upgraded troop can carry an army.
- If you are working toward B.O.B, one troop at level 18 is one of the four B.O.B Control tasks. The Baby Dragon is the usual pick because it unlocks early and works as a whole army.
- Run the Clock Tower while research is going. When active it runs Builder Base timers, research included, ten times faster, and a Clock Tower Potion does the same for 30 minutes.
Changes over time
- May 15, 2023 (Builder Base 2.0): Builder Hall 10 added, raising the lab to level 10 and troops to level 20. Troops now unlock at a minimum level instead of level 1, and existing troops kept any higher levels they already had.
FAQ
What resource does the Star Laboratory use?
Builder Elixir, both for upgrading the building and for every troop research.
Can I research while the Star Laboratory is upgrading?
Yes. A research already in progress keeps running. The new troop levels unlock when the lab upgrade finishes.
What is the max Star Laboratory level?
Level 10, at Builder Hall 10. It lets every troop reach level 20.
Sources: Supercell, Builder Base 2.0 full patch notes (May 15, 2023); in-game data. Checked October 1, 2026.
