Redstone clocks explained: repeater, hopper, and comparator clocks in Minecraft 26.2

A redstone clock is any circuit that switches itself on and off, over and over, without you touching it. That single idea powers an enormous amount of Minecraft: auto-farms that harvest on a timer, mob switches that pulse, hidden doors that reset, and any contraption that needs a steady heartbeat.

The problem is that "redstone clock" is not one thing. There are several designs, they run at wildly different speeds, and some of them will quietly wreck your server's tick rate if you use them wrong. This guide covers the three clocks worth knowing, when to reach for each, and the one mistake that turns a clock into a lag machine.

Everything here is pinned to Minecraft 26.2 Java Edition, where clock behavior is stable. Clocks are built entirely from the repeater and comparator, so if the terms "tick," "delay," or "signal strength" are fuzzy, read those first. For the full component map, keep the redstone handbook handy.

What "clock speed" actually means

Every clock has a period: the time for one full on-then-off cycle. Redstone timing is conventionally measured in redstone ticks, and one redstone tick equals 2 game ticks, which at the game's normal 20 game-ticks-per-second rate works out to 0.1 seconds. So a clock with a period of 20 redstone ticks (40 game ticks) fires once every 2 seconds. This guide gives every number in both units, redstone ticks for wiring it up, game ticks and seconds for knowing what you will actually feel.

Two facts shape every clock you build:

• Faster is not better. A clock that pulses every tick updates constantly, and dozens of them across a base add up to real server load. Most farms want the slowest clock that still keeps up.
• The signal needs to travel. A clock is only useful if its pulse reaches the machine it drives. Long lines need repeaters to survive the trip.

The repeater clock: simple and adjustable

The repeater clock is the one most players build first, and for good reason. It is a small loop of redstone that feeds back into itself through repeaters, and the repeater delays set the speed.

How it works: a redstone line loops back on itself so its own output re-triggers its input. Insert repeaters into the loop, and their combined delay sets the period. Add a torch or a lever tap to start it, and it pulses forever.

Exact timing: each repeater has four delay settings, and right-clicking a placed repeater cycles through them:

Setting	Delay per repeater
1st click (default)	1 redstone tick = 2 game ticks = 0.1s
2nd click	2 redstone ticks = 4 game ticks = 0.2s
3rd click	3 redstone ticks = 6 game ticks = 0.3s
4th click	4 redstone ticks = 8 game ticks = 0.4s

A clock's total period is the sum of every repeater's delay in the loop, doubled if the loop needs a symmetric on/off phase (most simple loops use one repeater carrying the whole delay for both the on and off half of the cycle, so a single repeater set to its slowest setting gives an 8-game-tick, 0.4-second on phase and the same for off, an overall period around 16 game ticks / 0.8 seconds for a minimal two-repeater loop, more if you chain further repeaters in).

• Strengths: dead simple, and the speed is tunable, just right-click the repeaters to change delay.
• Weaknesses: hard to make slow. To get a multi-second period you need a long chain of repeaters, which eats space fast, since 4 game ticks (0.2s) is the maximum any single repeater adds.
• Best for: short, fast pulses where you want easy speed control, like a rapid dispenser or a test rig.
• Torch burnout: a pure repeater loop (repeaters only, no torches in the loop) does not burn out, repeaters have no burnout mechanic. If you start or gate the loop with a redstone torch, that torch can burn out if it is forced to toggle more than 8 times within 60 game ticks (3 seconds), see the burnout section below.

The hopper clock: slow, compact, and reliable

When you need a slow clock, seconds or minutes per pulse, the hopper clock is the classic answer. It stores its timing in items instead of wire, so a long period stays physically small.

How it works: two hoppers face into each other, and a handful of items bounce back and forth between them. A comparator reads each hopper, and when the items finish moving to one side, the comparator flips the output. The pulse length is set by how many items you load in.

The formula, and where it comes from: a hopper has a fixed transfer cooldown of 8 game ticks (0.4 seconds) after it pushes or pulls an item, so a single hopper can move at most one item roughly every 8 ticks, a transfer rate of 2.5 items per second under ideal conditions. That 8-tick cooldown is the unit every hopper clock period is built from. The simplest hopper-loop clock, a basic two-hopper design with one item, runs on an 8-tick period; scaling it up to an N-hopper loop scales the period to roughly 4×N ticks per the wiki's documented designs. Loading more items into the loop stretches the period further, since each item adds its own transfer delay before the comparator sees the hopper empty out or fill up, which is why real-world designs range enormously: the wiki's documented Ethonian-style hopper clocks span from 8 ticks up to 256 seconds (4 minutes 16 seconds), and item-count multi-hopper designs (like SethBling's) are documented running from 1.6 seconds up to 512 seconds (8 minutes 32 seconds), purely by changing how many items are loaded and how the hoppers are chained. The wiki does not publish one universal "items in equals seconds out" formula that covers every hopper clock layout, because the period depends on both the item count and the specific circuit (how many hoppers, how they're chained, and whether a latch is used to force the items to flow one direction at a time). If you are tuning one for a specific period, the reliable method is to build the documented design you are copying and count items against its known behavior, not to assume a linear formula transfers between designs.

• Strengths: extremely compact for long delays, and rock-solid reliable. Two hoppers with enough items between them can hold a period of many minutes.
• Weaknesses: not instantly adjustable, you change the timing by adding or removing items, and it takes a moment to settle after you change the item count.
• Best for: auto-farms and mob switches that fire on a long, steady interval. This is the workhorse clock for most survival bases.
• Torch burnout: no torches in the loop, so a standard hopper clock does not burn out. Its output typically drives a repeater or comparator line downstream, which also has no burnout risk unless you insert a torch there.

Because each item adds a fixed unit of transfer delay, you can dial in a long period just by counting items in and out. A two-hopper design with a stack or more of items can comfortably run a farm that harvests once a minute or slower, all in a two-block footprint, smaller than any repeater chain that could hit the same period.

The comparator clock: the steady middle ground

The comparator clock uses a comparator's ability to read a decaying signal, producing a clean, repeating pulse without a huge repeater chain. It sits between the repeater clock's speed and the hopper clock's slow reliability.

How it works: a comparator feeds a subtracting loop so the signal builds and drains on a fixed cycle, producing a regular pulse. Adjusting the loop length changes the period.

Timing: a comparator's own signal processing takes 1 game tick per pass through it, the same as a repeater's fastest setting, so a comparator-based loop's period is set by how many comparators and repeaters are chained into the loop, exactly like a repeater clock's math, just with a comparator doing signal-strength subtraction somewhere in the ring instead of only delay. The wiki does not publish one fixed "comparator clock period" because, like the repeater clock, it scales with however many components you put in the loop; treat the ~1s to ~10s figure in the table below as the practical range most survival builds land in, not a hard limit of the circuit type.

• Strengths: compact, produces a clean pulse, and handles medium speeds well.
• Weaknesses: less intuitive to tune than a repeater clock, and easy to wire backward if you are new to subtract mode.
• Best for: medium-interval tasks where a repeater chain would be too bulky but a hopper clock too slow.
• Torch burnout: no burnout risk from the comparator or repeaters themselves; only a torch inserted into the loop can burn out.

Think of the three clocks as a speed ladder: repeater for fast, comparator for medium, hopper for slow. Almost every timing job in survival is solved by picking the right rung, not by inventing a new circuit.

Torch burnout: why some clocks stop working on their own

A redstone torch has a built-in safety mechanic: if it is forced to change state (on to off, or off to on) more than 8 times within 60 game ticks (3 seconds), it burns out. A burnt-out torch goes dark, stops responding to further state-change attempts, and only starts working again once the toggle count in that rolling 60-tick window drops back under 8. This is what "torch burnout" means when players warn you about it.

The practical rule for clocks: a clock built only from repeaters and comparators, with no redstone torch anywhere in the loop, cannot burn out, because only torches have this mechanic. That covers the repeater clock and comparator clock designs above when built as pure loops. Where burnout bites you is older or compact designs that use a torch inside the oscillating loop itself (classic "torch clocks" and some minimal comparator or repeater starter circuits that lean on a torch to kick the loop off and keep it going) or any circuit where a fast external clock forces a torch elsewhere in your build to toggle faster than 8 times per 3 seconds. If a torch in your build randomly goes dark under load, check whether something is toggling it past that threshold, that is burnout, not a bug.

The hopper clock has no torch in its item-transfer loop, so it does not burn out either, its comparator reads item count, not a torch state.

Which clock should you use?

Clock	Typical period	Footprint	Chunk-loading behavior	Lag cost	Best use
Repeater	2 game ticks (0.1s) per delay step up to 8 ticks (0.4s) per repeater; total period grows with chain length	Grows with delay, since slow periods need many repeaters in series	Only runs while its chunk is loaded	Low per-clock, but a fast loop updates every tick and many of them add up	Fast pulses, test rigs, dispensers
Comparator	Practically ~1s to ~10s in typical survival builds, scales with loop size like a repeater clock	Compact	Only runs while its chunk is loaded	Low; a comparator's subtract-mode read is cheap but still ticks every cycle	Medium-interval machines
Hopper	From 8 game ticks up to many minutes, set by item count and design (documented examples span 8 ticks to 256+ seconds)	Tiny for long delays, two hoppers can hold minutes of delay	Only runs while its chunk is loaded; a hopper's own item movement also needs the chunk simulated	Very low once settled, hoppers moving one item per 8-tick cooldown is cheap compared to a fast repeater loop	Farms, mob switches, anything on a long steady interval

Switching a clock off cleanly matters too: a repeater or comparator loop can be interrupted cleanly with a lever or a blocking signal fed into the loop, stopping it dead until re-triggered. A hopper clock is a little clumsier to switch off on demand, since its state lives in the items currently mid-transfer, but a redstone-controlled hopper (or a lever cutting its output line) still stops it from firing without disturbing the item count, so it resumes on the same timing once re-enabled.

If you take one rule away: use the slowest clock that still does the job. A crop farm that only needs to fire once a minute should never be driven by a fast repeater loop. The slower clock is smaller, lags less, and is easier to keep in one loaded chunk.

Turning a clock into a machine

A clock on its own just blinks. It becomes useful when its pulse drives something: a dispenser, a piston, a note block, or the harvesting mechanism of a farm. The pattern is always the same, clock produces a steady pulse, repeaters carry it to the machine, and the machine does its job on every beat.

Once you are comfortable with clocks, the next step is timed piston work, where the delay between two pulses decides whether a door opens cleanly or jams. That timing is covered in the piston doors guide, and the broader theory lives in the redstone handbook. A clock is simply a repeater delay that never stops, so the more comfortable you are with repeater timing, the more control you have over every machine you build.

Frequently asked questions

What is the simplest redstone clock?

A repeater clock: a small redstone loop that feeds back into itself through one or more repeaters. The repeater delays set the speed, and right-clicking them tunes it. It is the easiest clock to build but hard to make slow.

How do I make a slow redstone clock?

Use a hopper clock. Two hoppers face into each other with a handful of items bouncing between them, and a comparator reads when the items finish moving. The number of items sets the period, so two hoppers can hold a delay of many minutes in a tiny space.

Do redstone clocks cause lag?

Fast clocks can. A clock that fires every game tick floods the redstone update queue and can drag down a chunk's tick rate. Always use the slowest clock that still does the job, most farms only need a pulse every several seconds.

Why did my redstone clock stop when I walked away?

The chunk unloaded. A clock only ticks while its chunk is loaded, so a farm stops running once you leave its area. Keep timed farms near spawn chunks or inside your simulation distance.

What exactly is a repeater's delay in ticks?

A repeater has four settings, cycled by right-clicking it: 1 redstone tick (2 game ticks, 0.1s), 2 redstone ticks (4 game ticks, 0.2s), 3 redstone ticks (6 game ticks, 0.3s), and 4 redstone ticks (8 game ticks, 0.4s), the maximum. A loop's total period is the sum of every repeater's delay in it.

How does the hopper clock formula actually work?

A hopper has an 8-game-tick (0.4-second) cooldown after every item it pushes or pulls, that cooldown is the unit the whole clock is built from. A minimal two-hopper, one-item loop runs on roughly an 8-tick period; adding items or chaining more hoppers stretches the period, since each item adds its own transfer delay before the comparator flips. There is no single universal formula covering every hopper clock layout, the period depends on both item count and the specific circuit, so tune by copying a known design and counting items against its documented behavior.

Why do some redstone clocks burn out and others don't?

Only redstone torches burn out, and only if forced to change state more than 8 times within 60 game ticks (3 seconds). A clock built purely from repeaters and comparators, with no torch in the loop, cannot burn out, that covers the repeater and comparator clocks in this guide when built as clean loops, and the hopper clock entirely. Burnout only shows up in designs that use a torch inside the oscillating loop itself.