Plus–minus sign

A plus sign above a minus stroke, giving a tolerance or two possible values.

Also known as: Plus or minus, Tolerance sign, Margin of error sign

MathematicalScientificKeyboard & punctuationStandard profile

Meanings

The plus–minus sign states that a quantity may be added or subtracted — a measurement tolerance, a margin of error, or the two roots of a quadratic.

Common modern usageVerified fact
States a tolerance or uncertainty around a value, as in 20 ± 2, meaning anywhere from 18 to 22.
Contexts: Mathematics
Common modern usageVerified fact
Indicates that both the positive and negative case hold, as in the two solutions of a quadratic equation.
Contexts: Mathematics

An upright cross of two equal strokes, with a separate horizontal bar set directly beneath it.

Commonly confused with: Minus sign
Reciprocates the minus sign's warning: the plus–minus sign contains a minus stroke.
Composed of: Minus sign
The lower stroke.
Composed of: Plus sign
The upper element.

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Visual matchHigh confidence: High confidence because the visual match is defined by a current official standard.

Plus–minus sign
Wikipedia · retrieved 2026-07-30
Tertiary reference. Used for widely-agreed identity and origin summary, not for contested detail or exact dates.
Unicode Code Chart: Latin-1 Supplement (U+0080–U+00FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.

Last reviewed 2026-07-30

Meanings

The plus–minus sign states that a quantity may be added or subtracted — a measurement tolerance, a margin of error, or the two roots of a quadratic.

Common modern usageVerified fact

States a tolerance or uncertainty around a value, as in 20 ± 2, meaning anywhere from 18 to 22.

Common modern usageVerified fact

Indicates that both the positive and negative case hold, as in the two solutions of a quadratic equation.

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originLow confidence: Low confidence because the historical origin is documented in encyclopedic references, but only a single source has been found so far, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Visual matchHigh confidence: High confidence because the visual match is defined by a current official standard.

Sources

Plus–minus sign
Wikipedia · retrieved 2026-07-30
Tertiary reference. Used for widely-agreed identity and origin summary, not for contested detail or exact dates.
Unicode Code Chart: Latin-1 Supplement (U+0080–U+00FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.

Last reviewed 2026-07-30