Updated for Town Hall 18 (October 2026).
The Cannon Cart is a Builder Base ground troop that switches between a mobile cannon and a parked mortar. It unlocks at Builder Barracks level 7 (Builder Hall 5), starts at level 7 and maxes at level 20 on Builder Hall 10. Mortar Mode, added in Builder Base 2.0, gives it the longest reach of any Builder Base troop.
How the Cannon Cart works
It is the only Builder Base troop built on a defense instead of a Home Village troop. It has no favorite target: it rolls to the nearest building and shoots it, and turns on Guard Post troops or Zappies if they start a fight nearby. One Cannon Cart fills one Army Camp slot at every level.
Its ability is a mode switch you can use as often as you like:
- Cannon Mode is the default. The Cart drives around and fires single shots at ground targets from 4.5 tiles, every 1.2 seconds.
- Mortar Mode parks it. It cannot move, fires every 2.5 seconds, and deals splash damage from 8.5 tiles away. It hits any building in range except Walls (Walls next to a target still take splash). If nothing is in range, a red question mark appears over it.
While the Cart is in Cannon Mode, a green ring shows where Mortar Mode would reach if you switched right now. Since the Town Hall 18 update (November 17, 2025) you can trigger the switch instantly, and the Cart shows its range as soon as you deploy it.
Unlock and level stats
Build Builder Barracks level 7 at Builder Hall 5. After that, upgrades are researched in the Star Laboratory with Builder Elixir. Hitpoints and Cannon Mode damage go up on odd levels; Mortar Mode damage goes up on even levels.
| Level | Hitpoints | Cannon DPS | Cannon damage per shot | Mortar DPS | Mortar damage per shot | Research cost | Time | Star Lab |
|---|---|---|---|---|---|---|---|---|
| 7 | 666 | 115 | 138 | 60 | 150 | Unlocked | – | – |
| 8 | 666 | 115 | 138 | 68 | 170 | 1,000,000 | 1d | 5 |
| 9 | 732 | 130 | 156 | 68 | 170 | 1,100,000 | 1d 12h | 5 |
| 10 | 732 | 130 | 156 | 78 | 195 | 1,200,000 | 2d | 5 |
| 11 | 805 | 150 | 180 | 78 | 195 | 1,400,000 | 2d | 6 |
| 12 | 805 | 150 | 180 | 90 | 225 | 1,600,000 | 2d 12h | 6 |
| 13 | 886 | 170 | 204 | 90 | 225 | 2,400,000 | 3d 12h | 7 |
| 14 | 886 | 170 | 204 | 102 | 255 | 2,600,000 | 4d 12h | 7 |
| 15 | 974 | 190 | 228 | 102 | 255 | 3,400,000 | 5d 12h | 8 |
| 16 | 974 | 190 | 228 | 114 | 285 | 3,600,000 | 5d 12h | 8 |
| 17 | 1,072 | 215 | 258 | 114 | 285 | 4,100,000 | 6d | 9 |
| 18 | 1,072 | 215 | 258 | 130 | 325 | 4,300,000 | 6d | 9 |
| 19 | 1,179 | 240 | 288 | 130 | 325 | 5,300,000 | 6d 12h | 10 |
| 20 | 1,179 | 240 | 288 | 144 | 360 | 5,700,000 | 6d 12h | 10 |
Fixed stats: movement speed 19, spring weight 16.
How to attack with Cannon Carts
- The Cart hits hard but has low hitpoints. Send a tank first, either a Boxer Giant or the Battle Machine, and keep the Carts a few tiles back so one Multi Mortar shell cannot hit both.
- A common army is two or three slots of Boxer Giants with the rest Cannon Carts. With the Battle Machine available, two Giant slots is usually enough.
- Mortar Mode outranges short-range defenses such as the Double Cannon, Roaster and Mega Tesla. Park a Cart at the edge and let it pick those off. It is slow, so keep an eye on the clock.
- In Cannon Mode it can shoot over a two-tile gap between a Wall and a building, which is the gap many bases use to stop Sneaky Archers.
- If Stage 1 is clearly won, flipping the Cart into Mortar Mode stops it from wandering into traps. It enters Stage 2 with more health, and your hero gets extra time to charge its ability.
How to defend against Cannon Carts
- Kill the tank in front, and the Carts die fast. Crushers, Spring Traps and Double Cannons handle Boxer Giants; a Double Cannon burst can also kill a same-level Cart outright.
- Keep the Multi Mortar and Lava Launcher in the middle. Their splash catches both the Carts and whatever is tanking for them.
- Keep Crushers away from the edges. A Cart in Mortar Mode outranges them easily.
- A Hidden Tesla near the usual drop spots punishes a player who parks Carts at the edge for Mortar Mode.
Changes over time
- May 15, 2023 (Builder Base 2.0): Mortar Mode replaced the old Last Stand ability (which let a destroyed Cart keep firing for a few seconds); the Cart now unlocks at level 7; levels 19 and 20 opened at Builder Hall 10.
- May 15, 2023: B.O.B Control replaced the O.T.T.O Hut, whose second task had been a level 18 Cannon Cart. The new task accepts any troop at level 18.
- October 9, 2023: fixed a bug where switching modes while a Push Trap had the Cart in the air broke its position.
- November 17, 2025: the mode switch can be triggered instantly, and the Cart shows its range on deploy.
FAQ
What is the Cannon Cart’s range in Mortar Mode?
8.5 tiles, against 4.5 tiles in Cannon Mode.
Can you switch modes more than once?
Yes. Unlike most Builder Base abilities it is not a one-time use, so you can flip back and forth during the battle.
Do I still need a level 18 Cannon Cart for O.T.T.O?
No. Since May 2023, B.O.B Control accepts any Builder Base troop at level 18.
Sources: Supercell, Builder Base 2.0 full patch notes (May 15, 2023); Supercell, October 2023 update notes; Supercell, Town Hall 18 update notes (November 17, 2025); in-game data. Checked October 1, 2026.
