Clash of Clans Wiki
Clash of Clans Wiki
Clock Tower10
“The Clock Tower makes things happen faster in your village! Collect resources, research and build faster.”

Clock Tower Ruin
Clock Tower1
Level 1
Clock Tower2
Level 2
Clock Tower3
Level 3
Clock Tower4
Level 4
Clock Tower5
Level 5
Clock Tower6
Level 6
Clock Tower7
Level 7
Clock Tower8
Level 8
Clock Tower9
Level 9
Clock Tower10
Level 10


  • The Clock Tower is a building that can be repaired at Builder Hall Level 4. When activated, the Clock Tower will make timers in the Builder Base speed ten times as fast as normal for a short duration. This duration can be increased by upgrading the Clock Tower.
    • It will speed up resource collectors, construction, upgrades, and research timers.
  • Before the Clock Tower is repaired, it is treated similarly to an obstacle (much like the ruined Clan Castle) and cannot be moved around; attacking troops will not be able to attack or destroy it (nor do they need to do so in order to achieve 100% destruction). Once rebuilt, it can be moved freely around.
  • The Clock Tower will not reduce the Star Bonus cool-down time of Builder Battles.
  • The Clock Tower will occasionally make a free boost available. Once the free boost has been completely expended, there will be a 22-hour cool-down before the next free boost is available.
    • If the Clock Tower is not active, it can also be activated using Gems. A Clock Tower Potion can also be used to boost the Clock Tower for 30 minutes at any time (this duration is independent of Clock Tower level, and the potion works regardless of whether the Clock Tower is active).
  • Upgrading the Clock Tower will disable its ability to boost during the upgrade. It will also cancel any ongoing free boosts.

Strategies and Tips

  • Use the Clock Tower's boost when upgrading and/or researching something in the Builder Base. The Clock Tower will not, however, boost B.O.B when he is working in your Home Village.
    • Even if the Star Laboratory and Builders are inactive, it can still be useful to boost, as it still speeds up resource production slightly (gaining a few hours' worth of Builder Gold and Elixir).
  • You can also use the Clock Tower's boost for removing a lot of obstacles quickly. You can get a lot of gems in no time doing so.

Defensive Strategy

  • The Clock Tower is best placed outside the base as a distraction, as it serves little, if any, purpose on defense. Its 4×4 space makes it difficult to fit within the Walls. Additionally, due to its larger size, it may be easier to pick off than other buildings if defenses aren't placed properly.
  • The Clock Tower can be used to hide an opening in the Walls which can cause unexpected behavior in certain troops (such as Boxer Giants), and can also be used to funnel troops into Traps.

Upgrade Differences

  • Each time the Clock Tower is upgraded (depending on what level) you can see Roman numerals (I-X) on the left side that corresponds to the level of the Clock Tower.
  • The Clock Tower goes through significant visual changes at levels 1, 3, 5, 7, and 9.
    • At level 1, the Clock Tower is rebuilt from its broken state but parts are still in disrepair.
    • At level 2, the roof planks are fixed and reinforced.
    • At level 3, the front undergoes a major repair. A large ladder is placed on the front. The upright barrel at the side switches place with the sideways barrel. A trapdoor replaces the repairs on the roof. There is also additional stairs below the doorway. The Clock Tower becomes taller.
    • At level 4, the trapdoor hinges become metal and a metal frame under the trapdoor appears.
    • At level 5, the ladder is replaced by a cross in the front. You can also now see the gears inside through the "window" on the side of the tower.
    • At level 6, the holes in the trap door on top turns into a whole piece of metal.
    • At level 7, the front-bottom part gains two openings with one rotating gear each. The two front pillars gain some extra reinforcements and the side gains more steps.
    • At level 8, the hatch at the top of the tower is raised slightly, leaving a small opening where a bell can be seen.
    • At level 9, the gears are now golden while the hatch at the top of the tower is raised higher. The staircase receives railings on both sides.
    • At level 10, the golden gears have been replaced with a layer of stone bricks. A golden gear has been added below the clock. A lever or switch has been added and hooked up to the clock's mechanism. This lever moves left and and right approximately once per second.


Number Available Builder Hall Level
1 2 3 4 5 6 7 8 9 10
Total 0 0 0 1 1 1 1 1 1 1
Stage 1 Limit 1 1 1 1 1
Stage 2 Limit 0 0 0 0 0
Size Size
Boost Duration
Time Gained per Boost
Relative Boost* Catch-Up Point of Construction** Catch-Up Point of Boost*** Build Cost
Builder Gold
Build Time
Experience Gained
Builder Hall Level Required
Builder Hall
1 650 14m 2h 6m 9.4% 1 time N/A 150,000 2h 84 4
2 800 16m 2h 24m 10.8% 10 times N/A 180,000 3h 103 4
3 975 18m 2h 42m 12.1% 14 times N/A 220,000 4h 120 4
4 1,150 20m 3h 13.4% 20 times N/A 300,000 6h 146 4
5 1,350 22m 3h 18m 14.8% 40 times N/A 700,000 12h 207 5
6 1,600 24m 3h 36m 16.1% 80 times 1 time 1,200,000 1d 293 6
7 1,850 26m 3h 54m 17.4% 160 times 15 times 1,700,000 2d 415 7
8 2,150 28m 4h 12m 18.7% 240 times 30 times 2,200,000 3d 509 8
9 2,450 30m 4h 30m 20.0% 320 times 48 times 2,700,000 4d 587 9
10 2,750 32m 4h 48m 21.3% 400 times 67 times 3,700,000 5d 657 10

* Relative boost refers to the total time gain as a percentage of 22 hours (the cooldown for a free boost) plus boost duration (added because the cooldown starts countdown after the boost duration), and hence how much faster time will progress in your Builder Base on average. This is assuming that you activate the Clock Tower as soon as the 22 hour cooldown ends, and also assumes that you do not spend any Gems in activating the Clock Tower early.

** The Catch-Up Point of Construction is the minimum number of boosts for which the newly upgraded Clock Tower has equaled the time for upgrading the Clock Tower had it not been upgraded - this does not consider recovering the cost of the Gold required to perform the upgrade.

The formula of Catch-Up Point of Construction time is:

*** The Catch-Up Point of Boost is the minimum number of boosts for which the newly upgraded Clock Tower has provided enough time gain such that the time lost by the inability to immediately use the free boost due to the construction of the Clock Tower is negated. This does not apply to Clock Towers level 5 and below, whose construction time is less than the current cooldown time of 22 hours.

The formula of Catch-Up Point of Boost is:

(given that )


Icon Descriptions

Icon UpgradeTapping this icon begins upgrading the Clock Tower to the next level, if you have enough resources and a free Master Builder or O.T.T.O. When the Clock Tower is at maximum level, this icon is not shown.
Icon HoBTapping this icon instantly upgrades the Clock Tower to the next level, at the cost of one Hammer of Building if you have one. When the Clock Tower is at maximum level, or the Builder Hall requirements for the next level are not met, this icon is not shown.
Icon FinishNowTapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of the displayed number of Gems.
Icon FinishNowBoBTapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Building. This icon is only shown if you have at least one Book of Building.
Icon FinishNowBoETapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Everything. This icon is only shown if you have at least one Book of Everything but do not have a Book of Building.
Icon CancelTapping this icon, which is displayed only while an upgrade is in progress, cancels the current upgrade and refunds half of the upgrade cost.
Icon FreeBoostTapping this icon activates the Clock Tower, boosting timers in the Builder Base by a factor of ten for a duration determined by the level of the Clock Tower. This icon is only displayed when a free boost is available.
Icon ClockTowerPotionTapping this icon activates the Clock Tower, boosting timers in the Builder Base by a factor of ten for 30 minutes, at the cost of one Clock Tower Potion. This icon is only displayed if you have at least one Clock Tower Potion.
Icon BoostNowTapping this icon allows you to boost the Clock Tower before its free boost is available, at the cost of the displayed amount of Gems. This icon is only displayed when the Clock Tower's free boost is in cooldown.
Icon ResumeTapping this icon resumes a paused Clock Tower boost. This icon is only shown if you have an active Clock Tower boost that was paused by a maintenance break.


Patch Type Description
May 22, 2017 Release The Clock Tower was added with the original release of the Builder Base, with 5 levels. Clock Tower Ruin Clock Tower1 Clock Tower2 Clock Tower3 Clock Tower4 Clock Tower5
June 27, 2017 Update
  • Added the level 6 Clock Tower. Clock Tower6
  • Clock Tower cool-down reduced from 8 hours to 7 hours. Time
  • Clock Tower duration reduced by 50% to 2.5 minutes. Time
  • Clock Tower speed multiplier reduced from 10x to 8x. Time
September 27, 2017 Update Added the level 7 Clock Tower. Clock Tower7
March 5, 2018 Update Added the level 8 Clock Tower. Clock Tower8
June 18, 2019 Update Added the level 9 Clock Tower. Clock Tower9
March 30, 2020 Balance changes
  • Multiplier increased from 8x to 10x. Time
  • Boost duration has been increased from 3-11 minutes to 14-30 minutes. Time
  • Cool-down time has been increased from 7 hours to 22 hours, but the Gem price to skip the cool-down has been reduced. TimeGems
October 12, 2020 Update Clock Tower boost no longer pauses during maintenance breaks.
October 26, 2020 Optional Update Fixed Clock Tower boosts that could not be resumed if they were already paused before the update maintenance.
May 15, 2023 Update Added the level 10 Clock Tower. Clock Tower10


  • The Clock Tower sits with the rest of the obstacles on the western side of the map when broken.
  • Above the door of the Clock Tower, you can see Roman numerals which correspond to the building's level. This can also be observed on the Star Laboratory.
  • The Clock Tower is the only building in the game that has its changes stated in the description while prompting an upgrade (i.e "Makes boost last 2m longer").
  • The Clock Tower's hand makes a full rotation every 30 seconds.
  • While a boost is active, most animations also appear to speed up as well. The Master Builder, Villagers as well as Troops stationed in Guard Posts and Army Camps move faster (the latter is purely aesthetic; troops will not move or attack faster during a Battle while under a boost).
  • Interestingly, when fixing the three broken buildings in the Builder Base, the Gem Mine and Battle Machine fixes are called a “rebuild”, while the Clock Tower is called a “repair”. In fact, the Clock Tower is the most broken out of the three, thus the one that needs a rebuild the most.
  • The Clock Tower's destroyed state is the same as the Town Hall's or Builder Hall's.
  • The Clock Tower could've been inspired by the Builder's Workshop, the 6th Arena of Clash Royale.
  • When a maxed Clock Tower is paired with a maxed Gem Mine, one boost will net a player 90% of a gem.
Builder Base Buildings
Defensive Buildings CannonDouble CannonArcher TowerHidden TeslaFirecrackersCrusherGuard PostAir BombsMulti MortarO.T.T.O's Outpost (Zappy) • RoasterGiant CannonMega TeslaLava LauncherX-BowWalls
Traps: Push TrapSpring TrapMineMega Mine
Resource Buildings Builder Hall (Magic Items) • Gold MineElixir CollectorGold StorageElixir StorageGem MineB.O.B Control
Army Buildings Builder BarracksArmy CampStar LaboratoryBattle Machine AltarReinforcement CampHealing HutBattle Copter Altar
Other Buildings BoatDecorationsObstaclesClock TowerElixir Cart