XNOR GATE (EXCLUSIVE NOR)
Outputs ON when both inputs are the same (both ON or both OFF). The inverse of XOR. Used for equality comparison, combination locks, and parity circuits.
Truth Table
| Input A | Input B | Output |
|---|---|---|
| 0 (OFF) | 0 (OFF) | 1 (ON) |
| 0 (OFF) | 1 (ON) | 0 (OFF) |
| 1 (ON) | 0 (OFF) | 0 (OFF) |
| 1 (ON) | 1 (ON) | 1 (ON) |
Overview: what the XNOR Gate (Exclusive NOR) is and does
Outputs ON when both inputs are the same (both ON or both OFF). The inverse of XOR. Used for equality comparison, combination locks, and parity circuits.
In plain terms, the output is on when both inputs are the same, whether both on or both off. XNOR is the equality gate: it answers 'do these two signals match?', which makes it the natural core of combination locks and bit-comparison circuits.
This page describes the gate as it behaves in Java Edition 1.21; the truth table and timings below match vanilla redstone exactly.
How it works: the redstone mechanics
Across its four input combinations the output is on in 2 cases — A off with B off and A on with B on — and off in the remaining 2.
Expressed as boolean algebra that is output = NOT (A XOR B).
Built as XOR followed by a NOT gate, it adds one extra redstone tick on top of the XOR it is based on.
Because redstone signals are just on or off, "on" here means a powered line (signal 1-15) and "off" means an unpowered line (signal 0); the gate cares only about presence or absence of power, not its exact strength.
How to build it
- 1Build an XOR gate (see XOR instructions).
- 2Add a NOT gate (block + torch) to the XOR output.
- 3The result inverts the XOR, giving XNOR behavior.
- 4Alternative: Use comparators in compare mode, output is ON when both inputs match.
- 5Verify it against the truth table: setting the inputs to OFF and OFF should drive the output ON. Walk through every input combination once to confirm the gate matches the table above.
Uses & applications
- ▸XNOR is the equality gate: it answers 'do these two signals match?', which makes it the natural core of combination locks and bit-comparison circuits.
- ▸XOR + NOT (simplest, add inverter to XOR output) — a practical build choice for this gate.
- ▸Comparator XNOR (two comparators in compare mode feeding OR) — a practical build choice for this gate.
- ▸6-torch XNOR (compact torch-only design) — a practical build choice for this gate.
- ▸Combination lock core (check if input matches key) — a practical build choice for this gate.
Tips & common mistakes
- !Keep your inputs isolated with repeaters if signals are flowing back into each other; uncontrolled backflow between dust lines is the most common reason a gate reads the wrong value.
- !Remember the propagation cost: built as XOR followed by a NOT gate, it adds one extra redstone tick on top of the XOR it is based on. If you chain several gates, those ticks add up and can desynchronise a fast circuit.
- !When a multi-gate circuit misbehaves, test each gate in isolation against its own truth table before assuming the wiring between them is at fault.
XNOR Gate (Exclusive NOR) FAQ
What does a XNOR Gate (Exclusive NOR) do in Minecraft?
A XNOR Gate (Exclusive NOR) outputs a signal where the output is on when both inputs are the same, whether both on or both off. In boolean terms, output = NOT (A XOR B).
What is the truth table of a XNOR Gate (Exclusive NOR)?
Across its four input combinations the output is on in 2 cases — A off with B off and A on with B on — and off in the remaining 2. The boolean expression is output = NOT (A XOR B).
How do you build a XNOR Gate (Exclusive NOR) with redstone?
Build an XOR gate (see XOR instructions). Add a NOT gate (block + torch) to the XOR output. Common variants include XOR + NOT (simplest, add inverter to XOR output) and comparator XNOR (two comparators in compare mode feeding OR).
How much delay does a XNOR Gate (Exclusive NOR) add?
Built as XOR followed by a NOT gate, it adds one extra redstone tick on top of the XOR it is based on. That matters most in clocks and adders where every redstone tick counts.