XOR gate
An XOR (exclusive OR) gate’s output is 1 when its inputs differ and 0 when they are the same. Its symbol is the OR gate’s shape with a second curved line behind its back.
Easily confused with
How to read it
Kuphaldt’s Lessons in Electric Circuits gives the rule: the output is high if the inputs are at different logic levels, 0 and 1 or 1 and 0, and low if they are the same. It differs from the OR gate only when both inputs are 1. Boolean algebra writes XOR with a circled plus, Y = A ⊕ B, as Texas Instruments does for each gate on its SN74HC86; Unicode also has a separate ⊻ named XOR. Kuphaldt lists comparing binary numbers bit for bit, error detection (parity checks) and code conversion among the gate’s uses.
Also searched as: ⊕, =1, EOR, exclusive OR, XOR gate symbol, XOR truth table.
Truth table
| A | B | Y = A ⊕ B |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
The two standard shapes
Distinctive shape ANSI/IEEE Std 91: the OR shape with a second curve behind it. Rectangular shape IEC 60617-12: a box marked =1.
The rectangular form is a box marked =1. Texas Instruments’ guide to IEEE Std 91 defines it as one and only one input active to activate the output, and gives a separate qualifying symbol, 2k + 1, for an odd number of active inputs. With two inputs the two come to the same truth table.
Look-alikes
The OR gate has a single curved back. The XNOR gate is the XOR shape with a small circle at the output.
Read next
- Next in Logic gate symbolsXNOR gateAn XNOR (exclusive NOR) gate’s output is 1 when its inputs are the same and 0 when they differ. Its symbol is the XOR gate’s shape with a small circle at the output.
- The same shape in Accessibility symbolsAssistive listening symbol (ear)An ear with a diagonal bar across it is the International Symbol of Access for Hearing Loss. It marks an assistive listening system: a loop, infrared or FM system that sends sound to hearing aids or headsets.
More logic gate symbols
The same shape elsewhere
Browse symbols drawn with 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 Exclusive-OR gate
- Overview of IEEE Standard 91-1984: Explanation of Logic Symbols, SDYZ001A, 1996, Texas Instruments, Table 1, General qualifying symbols
- SNx4HC86 Quadruple 2-Input XOR Gates (data sheet), SN74HC86 data sheet, Texas Instruments, 3 Description
- ECE 205 Electrical and Electronics Circuits, Lecture 30, Prof. Umberto Ravaioli, Spring 2026, University of Illinois Urbana-Champaign, Slide 9, truth tables
- Mathematical Operators, Range: 2200–22FF (code chart), The Unicode Standard, Unicode Consortium, U+2295 and U+22BB
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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