Updated for Town Hall 18 (October 2026).
The Clock Tower makes every timer in your Builder Base run 10 times faster while its boost is active. The boost lasts 14 minutes at level 1 and 32 minutes at level 10, which works out to between 2 hours 6 minutes and 4 hours 48 minutes of building, research and resource time per boost. It only affects the Builder Base, never the Home Village.
How the Clock Tower boost works
Tap the Clock Tower and start the boost. For the next few minutes, the Builder Base clock runs at 10x speed, so one real minute counts as ten. Everything with a timer moves faster at once:
- building and upgrade timers for every builder working on the Builder Base
- research in the Star Laboratory
- production in your Gold Mines, Elixir Collectors and the Gem Mine
Because one boost speeds up all of these together, the best time to start it is when all your Builder Base builders and the Star Laboratory are busy. A boost with idle builders still adds a few hours of mine and collector output, so it is never fully wasted.
The free boost has a 22-hour cooldown, and that cooldown only starts counting after the boost itself ends. If you want another boost before the timer runs out, you can pay Gems, or use a Clock Tower Potion from your magic items. The potion always gives a 30-minute boost, whatever level your Clock Tower is, and you can drink it even while a free boost is running.
Two things the Clock Tower does not touch: the Star Bonus timer from Builder Base battles, and B.O.B when he is building in your Home Village. Troops in battle also do not speed up. You may see Army Camp troops and villagers moving quicker during a boost, but that is only animation.
Clock Tower levels, boost time and upgrade cost
The Clock Tower starts as a ruin on the west side of the map. You can repair it once your Builder Hall reaches level 4, and the 10th and final level arrived with Builder Hall 10. It takes up a 4×4 space. Each level adds 2 minutes of boost, which is 18 extra minutes of Builder Base time per use.
| Level | Builder Hall needed | Boost length | Time gained per boost | Hitpoints | Cost (Builder Gold) | Build time |
|---|---|---|---|---|---|---|
| 1 | 4 | 14m | 2h 6m | 650 | 150,000 | 2h |
| 2 | 4 | 16m | 2h 24m | 800 | 180,000 | 3h |
| 3 | 4 | 18m | 2h 42m | 975 | 220,000 | 4h |
| 4 | 4 | 20m | 3h | 1,150 | 300,000 | 6h |
| 5 | 5 | 22m | 3h 18m | 1,350 | 700,000 | 12h |
| 6 | 6 | 24m | 3h 36m | 1,600 | 1,200,000 | 1d |
| 7 | 7 | 26m | 3h 54m | 1,850 | 1,700,000 | 2d |
| 8 | 8 | 28m | 4h 12m | 2,150 | 2,200,000 | 3d |
| 9 | 9 | 30m | 4h 30m | 2,450 | 2,700,000 | 4d |
| 10 | 10 | 32m | 4h 48m | 2,750 | 3,700,000 | 5d |
If you use every free boost the moment it comes off cooldown, a level 10 Clock Tower makes your Builder Base progress about 21% faster on average. At level 1 the figure is about 9%.
Is upgrading the Clock Tower worth it?
Usually yes, but time it well. While the Clock Tower is upgrading you cannot boost, and starting the upgrade cancels a free boost that is still running. Start the upgrade right after a boost ends, so you lose as little boost time as possible.
The early levels pay back almost at once: a level 1 to level 2 upgrade costs 3 hours of building and gives back 18 extra minutes per boost. The later levels take longer. Working it through, the level 10 upgrade (5 days) needs 400 boosts before the extra 18 minutes per boost has repaid the build time, which is more than a year of daily boosts. Push it up when a builder would otherwise sit idle, and put walls, defenses and the Builder Hall first when gold is tight.
Where to place the Clock Tower
The Clock Tower has no defensive use, and its 4×4 footprint is awkward to fit inside walls. Most players leave it outside the main base, where it pulls ground troops away from the core for a few seconds. You can also park it in front of a gap in your walls or use it to steer troops toward a trap. Before it is repaired it acts like an obstacle: attackers cannot hit it, and it does not count toward the destruction percentage.
Clock Tower changes over time
- May 22, 2017: added with the original Builder Base, with 5 levels.
- June 27, 2017: speed cut from 10x to 8x and cooldown changed from 8 to 7 hours.
- March 30, 2020: speed raised back to 10x, boosts lengthened to 14-30 minutes and the free-boost cooldown raised to 22 hours, with cheaper Gem skips.
- October 12, 2020: boosts stopped pausing during maintenance breaks.
- May 15, 2023: level 10 added in the Builder Base 2.0 update.
Since Builder Base 2.0, the Clock Tower’s role has not changed, but there is more for it to speed up. O.T.T.O works as a second Builder Base builder from Builder Hall 6, and since May 2026 you can add one more Builder Base builder (from Builder Hall 2) once all your Home Village builders are unlocked.
Clock Tower FAQ
How fast does the Clock Tower speed things up?
10x. Every minute of boost counts as 10 minutes of Builder Base time, so you gain 9 extra minutes for each minute the boost runs.
Does the Clock Tower work in the Home Village?
No. It only speeds up Builder Base timers. It will not speed up B.O.B while he is working in the Home Village, and it does nothing for your Home Village builders, Laboratory or collectors.
How much time does the Clock Tower save?
From 2 hours 6 minutes per boost at level 1 to 4 hours 48 minutes at level 10. A Clock Tower Potion always gives 30 minutes of boost, which is 4 hours 30 minutes of Builder Base time.
How often can I use the free boost?
Once the boost ends, a 22-hour cooldown starts. Gems or a Clock Tower Potion let you boost again sooner.
Sources: Supercell release notes (Builder Base 2.0 full patch notes (Supercell, May 15, 2023), May 2026 update notes (Supercell)) and in-game data.
