REDSTONE COMPARATOR
A versatile component with two modes: compare mode (outputs back signal if back >= side) and subtract mode (outputs back - side). Can also read container fullness as an analog signal.
Crafting Recipe
3 Stone + 3 Redstone Torches + 1 Nether Quartz → 1 Redstone Comparator
Signal Behavior
Input
InputBack input and side inputs
Output
Compare: back signal if back >= side (else 0). Subtract: back - max(sides), min 0.
Max Signal Strength
15
Delay
1 redstone tick
Modes
- Compare mode (front torch off)
- Subtract mode (front torch on)
Crafting Redstone Comparator: the grid and what it all costs
To craft Redstone Comparator you place 3 Redstone Torch, 3 Stone and 1 Quartz in the shape below, which fills a 3x3 corner of the grid. That is 7 items for a single Redstone Comparator.
Most of that is Redstone Torch: 3 of the 7 squares, so stock up on that before you start on Redstone Comparator.
Where each item goes in the 3x3 Redstone Comparator grid
| Goes into Redstone Comparator | Amount in the grid |
|---|---|
| Redstone Torch | 3 |
| Stone | 3 |
| Quartz | 1 |
| Redstone Comparator out of one craft | 1 |
Read straight off the Redstone Comparator recipe in Java Edition 26.2.
What the Redstone Comparator is, and what it does for you
A versatile component with two modes: compare mode (outputs back signal if back >= side) and subtract mode (outputs back - side). Can also read container fullness as an analog signal.
As a transmission component its job is to carry, refresh, or reshape a signal as it moves between other blocks. It is the analog brain of redstone, the only component that can measure container fullness and do arithmetic on signal strengths.
The Redstone Comparator was added to Minecraft in 1.5; everything below is its Java Edition 26.2 behaviour.
Inside the Redstone Comparator: what the signal actually does
On the input side, back input and side inputs. On the output side, compare: back signal if back >= side (else 0). Subtract: back - max(sides), min 0..
In compare mode (front torch dark) it passes the back signal through unless a side input is stronger, in which case it outputs 0. In subtract mode (front torch lit) it outputs back minus the strongest side, floored at 0. Pointed out of a container it reads how full that container is as a signal from 0 to 15.
Timing-wise, factor in 1 redstone tick when you wire it into a sequenced circuit.
It can output a maximum signal strength of 15, which travels 15 blocks through bare redstone dust before fading to nothing.
These are the modes you can put the Redstone Comparator into, and each one changes what comes out: compare mode (front torch off) and subtract mode (front torch on).
How to set up the Redstone Comparator
- 1Craft the Redstone Comparator: 3 Stone + 3 Redstone Torches + 1 Nether Quartz → 1 Redstone Comparator.
- 2Set the Redstone Comparator down facing the way the signal has to travel, on a block that will actually hold it in place, with the dust already run out on the far side.
- 3Wire dust into its input side and read the refreshed or modified signal off its output side, keeping its facing in mind.
- 4Before it goes anywhere near a real build, run the Redstone Comparator on its own a few times over and check every result against the timing figures listed above this step.
Where the Redstone Comparator earns its keep
- ▸Container fullness detection
- ▸Analog signal processing
- ▸Subtraction circuits
- ▸Item sorting
- ▸Signal comparison
Tips & common mistakes
- !Confusing compare vs subtract mode
- !Side inputs override if stronger in compare mode
- !Reading containers requires specific placement
- !Mixing up compare and subtract mode is the classic comparator bug, check whether the little front torch is lit before blaming your wiring.
Redstone Comparator FAQ
What do redstoners actually build with the Redstone Comparator in Minecraft?
The Redstone Comparator is most often used for container fullness detection, analog signal processing, subtraction circuits, and item sorting. As a transmission component its job is to carry, refresh, or reshape a signal as it moves between other blocks.
How far does the Redstone Comparator push a signal?
Up to 15 out of the Redstone Comparator, and not a level more than that. Compare: back signal if back >= side (else 0). Subtract: back - max(sides), min 0.
How do you craft the Redstone Comparator?
3 Stone + 3 Redstone Torches + 1 Nether Quartz → 1 Redstone Comparator. It was introduced in 1.5.
Does the Redstone Comparator add any delay to a circuit?
Yes, 1 redstone tick. Account for that timing when chaining it with other components, especially in clocks and fast doors.
How does a comparator read a chest?
Point the comparator's back into the chest (or place it one block away facing the chest). It outputs a signal from 0 (empty) to 15 (full) scaled to how full the container is, accounting for stack sizes. A single item in a large double chest produces signal 1.
Components that connect to Redstone Comparator
Redstone Comparator does not stand on its own. 3 other component pages are tied to it:
Mining Redstone Comparator: how hard, how bright and how tough
Redstone Comparator breaks the instant you touch it: hardness 0, so your bare hand is as fast as any tool.
Redstone Comparator resists explosions to 0, the same as its hardness, which means TNT clears it. No light comes off Redstone Comparator, so torch the area around it if that matters.
| Redstone Comparator | Java Edition value |
|---|---|
| Redstone Comparator hardness | 0 |
| Redstone Comparator blast resistance | 0 |
| Fastest tool on Redstone Comparator | no tool in particular |
| Light out of Redstone Comparator | 0 |
