NAND gate
A NAND gate is an AND gate with its output inverted: the output is 0 only when all inputs are 1, and 1 otherwise. Its symbol is the AND gate’s D shape with a small circle at the output.
Easily confused with
How to read it
The name is a contraction of NOT and AND. Kuphaldt’s Lessons in Electric Circuits describes the gate as an AND gate with an inverter on its output, and the bubble on the output line marks that inversion. In Boolean algebra NAND is an AND with a bar over the whole expression, NOT (A·B): Texas Instruments’ data sheet for the SN74HC00, four 2-input NAND gates, gives each gate’s function as A ● B with the bar across both letters. Unicode encodes ⊼ as NAND.
NAND and NOR are the universal gates: given enough of them, either type can mimic any other gate, Kuphaldt writes, and digital control systems have been designed around nothing but NAND gates or NOR gates.
Also searched as: 7400, NAND gate symbol, NAND gate truth table, NOT AND, universal gate.
Truth table
| A | B | Y = NOT (A·B) |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
The two standard shapes
Distinctive shape ANSI/IEEE Std 91: the AND gate’s D shape with a circle. Rectangular shape IEC 60617-12: a box marked &, with a circle at the output.
The same gate drawn as an OR
An OR gate with bubbles on both inputs, which Kuphaldt calls a negative-OR gate, has the same truth table as a NAND gate.
Look-alikes
The AND gate is the same D shape without the circle. The NOR gate has the circle on the OR shape.
Read next
- Next in Logic gate symbolsNOR gateA NOR gate is an OR gate with its output inverted: the output is 1 only when all inputs are 0. Its symbol is the OR gate’s shape with a small circle at the output.
- The same shape in Air Force ranksChief master sergeant (E-9)Chief master sergeant, pay grade E-9: the highest of the senior noncommissioned officer ranks in the US Air Force. The insignia is five stripes below a star in a circle and three stripes above it.
More logic gate symbols
The same shape elsewhere
Browse symbols drawn with circles, curves and waves or lines.
Sources
- Lessons In Electric Circuits, Volume IV: Digital, chapter 3, Logic Gates, Tony R. Kuphaldt, open textbook (Design Science License), Tony R. Kuphaldt (ibiblio), The NAND gate; The Negative-OR gate; Gate universality
- SNx4HC00 Quadruple 2-Input NAND Gates (data sheet), SN74HC00 data sheet, Texas Instruments, 3 Description
- Overview of IEEE Standard 91-1984: Explanation of Logic Symbols, SDYZ001A, 1996, Texas Instruments, Table 1; Table 2
- ECE 205 Electrical and Electronics Circuits, Lecture 30, Prof. Umberto Ravaioli, Spring 2026, University of Illinois Urbana-Champaign, Lecture summary; universal gates
- Mathematical Operators, Range: 2200–22FF (code chart), The Unicode Standard, Unicode Consortium, U+22BC
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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