Updated 25 October 2026. Facts on this page come from minecraft.wiki, minecraft.net and the live Artemis PvP server; sources are listed at the bottom.
Redstone Comparator in Minecraft: How It Works and Uses
A redstone comparator reads and compares signals. In compare mode it passes the back signal only if the side signal is not stronger; in subtract mode it outputs the back minus the side. It also reads containers, giving a signal from 0 to 15 based on how full they are, which drives item sorters.
How do you craft a redstone comparator?
3 redstone torches, 1 Nether quartz and 3 stone. Right-click to switch modes; the front torch lights up in subtract mode. It reads chests, furnaces, hoppers, jukeboxes, cauldrons, lecterns, cake and more.
What is it used for?
- Item sorters
- Full-chest alarms
- Detecting a disc or a lectern page
- Pulse and clock circuits
More: item sorters.
More about the redstone comparator
Facing away from a chest it gives 0 for empty up to 15 for full. It also reads cake slices, cauldron levels, composter fill, lectern pages and end portal frames with eyes. In subtract mode the small torch at the front lights up.
Where does it fit in redstone?
Redstone parts fall into power sources (levers, buttons, plates, torches, observers), wiring (dust, repeaters, comparators) and mechanisms (pistons, dispensers, droppers, hoppers, lamps and doors). Most circuits combine one of each: something to detect, something to carry the signal, and something to act. Signals move along dust at once, while each torch, repeater or comparator adds a small delay measured in redstone ticks of 0.1 seconds. Start with redstone basics.
Tips
A comparator facing away from a jukebox tells you which disc is playing, a common trick in music boxes. Signal strength: signal strength.
Frequently asked questions
What does a comparator do?
Compares or subtracts signals and reads containers.
Sources
Every fact on this page was checked against these pages; the wording is ours.