Convert
Repeater chain
Hopper clock
Two hoppers pointing into each other with a comparator reading one of them. The items drain across at one every 8 ticks, so a stack of 64 is 25.6 seconds a side. Anything over 320 items needs more than one stack and the extra slots change nothing about the speed.
Repeater2, 4, 6 or 8Delay per notch, one to four redstone ticksRepeaterBlock.getDelay: DELAY * 2
Comparator2Delay before its output follows a changeComparatorBlock.getDelay
Redstone torch2Delay to turn on or offRedstoneTorchBlock.TOGGLE_DELAYRedstone torch burnout160Stays off after 8 toggles within 60 ticksRedstoneTorchBlock RECENT_TOGGLE_TIMER 60, MAX_RECENT_TOGGLES 8, RESTART_DELAY 160
Observer2 + 2Fires 2 ticks after it sees a change, pulse lasts 2 ticksObserverBlock scheduleTick(2) twice
Piston extend2Ticks to push out (and to pull back)PistonMovingBlockEntity.TICKS_TO_EXTEND
Hopper8 per itemOne item moved, then an 8 tick cooldownHopperBlockEntity.MOVE_ITEM_SPEED
Dispenser and dropper0Fires on the tick it is powered, no scheduled delayDispenserBlock (TRIGGER_DURATION 4 is only its triggered flag)
Redstone lamp0 on, 4 offLights at once, waits 4 ticks before going darkRedstoneLampBlock scheduleTick(4)
Stone button20Stays pressed for 1 secondBlocks: new ButtonBlock(BlockSetType.STONE, 20)
Wooden button30Stays pressed for 1.5 seconds (every wood, bamboo, crimson, warped)Blocks: new ButtonBlock(BlockSetType.OAK, 30)
Pressure plate20Rechecks and releases 20 ticks after the last entity leavesBasePressurePlateBlock.getPressedTime
Weighted pressure plate10Rechecks every 10 ticksWeightedPressurePlateBlock.getPressedTime
Target block20 or 8Signal lasts 20 ticks for an arrow or trident, 8 for anything elseTargetBlock ACTIVATION_TICKS_ARROWS, ACTIVATION_TICKS_OTHER
Sculk sensor30 + 10Active for 30 ticks, then a 10 tick cooldownSculkSensorBlock ACTIVE_TICKS, COOLDOWN_TICKS
Tripwire hook10Rechecks the wire every 10 ticks while something stands on itTripWireHookBlock.RECHECK_PERIOD
Lectern2Pulse when a page is turnedLecternBlock.PAGE_CHANGE_IMPULSE_TICKS
Crafter4Crafts 4 ticks after the pulse, animates for 6CrafterBlock CRAFTING_TICK_DELAY 4, MAX_CRAFTING_TICKS 6
Daylight detectorevery 20Re-reads the sky once a secondDaylightDetectorBlock: gameTime % 20
Lever, note block, copper bulb0No scheduled delay; they change on the tick they are poweredLeverBlock, NoteBlock, CopperBulbBlock: no scheduleTickGame ticks and redstone ticks
The game ticks 20 times a second and that is the only clock it has. A "redstone tick" is a convention: the 2 game ticks a repeater adds per notch. Every delay on this page is in game ticks because that is what the code schedules, and every number comes from the class named next to it in the table above.
A few delays surprise people. A dispenser and a dropper have no delay at all: the 4-tick value in their code only resets their "triggered" state and does not slow the shot. A redstone lamp lights the tick it is powered but waits 4 ticks before it goes dark, which is why a lamp on a fast clock looks on more than off. A sculk sensor is busy for 40 ticks a hit, 30 active plus a 10 tick cooldown, so it cannot react faster than twice a second.
Sizing a clock
For anything under a couple of seconds, repeaters are the simplest clock: the loop's period is the sum of its notches, 2 game ticks each. For longer timings a hopper clock is cheaper and exact, because every item in the loop adds 8 game ticks to each side, so 25 items is a 10 second side and 150 is a minute. Past 64 items the clock needs more than one stack in the hopper, which works fine. A repeater chain for a minute would need 150 repeaters, which is why nobody builds one.
Frequently Asked Questions
How long is a redstone tick?
Two game ticks, which is 0.1 seconds. The game runs 20 ticks a second and a repeater adds 2 game ticks per notch, so the notches, one to four, are one to four redstone ticks. Most redstone guides count in redstone ticks for that reason; the game itself only ever schedules game ticks.
How many repeaters do I need for a 1 second delay?
Three: two at 4 and one at 2. Four notches is 8 game ticks (0.4 s), so 1 second is 20 game ticks, which is 4 + 4 + 2 notches. The calculator's repeater panel does this for any delay and lists the fewest repeaters that add up to it.
How fast does a hopper move items?
One item every 8 game ticks, 2.5 items a second, so a full stack of 64 takes 25.6 seconds. That is HopperBlockEntity.MOVE_ITEM_SPEED in the game code and it is the whole basis of a hopper clock: a half cycle is 8 game ticks per item in the loop.
How do I make a hopper clock with a specific timing?
Point two hoppers into each other, put a comparator against one of them, and drop items in. The signal flips each time all the items have crossed, so the number of items sets the timing: items times 8 game ticks a side. For a 10 second side you need 25 items; for a minute, 150. Type the seconds you want into the calculator and it gives the item count.
Why does my redstone torch burn out?
A torch that toggles 8 times within 60 game ticks (3 seconds) burns out and stays off for 160 game ticks (8 seconds) before it restarts. Fast clocks built from torches hit that limit; use a repeater, comparator or observer clock instead, none of which burn out.
What is the delay of an observer?
An observer fires 2 game ticks after it sees a change and its pulse lasts 2 game ticks, so an observer line passes a signal along at one redstone tick per block.
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