What ± means, how to type it, and how it differs from ∓ — click to copy.
Click to copy · U+00B1
| Property | Value |
|---|---|
| Character | ± |
| Unicode code point | U+00B1 |
| Unicode name | PLUS-MINUS SIGN |
| Unicode block | Latin-1 Supplement |
| Category | Math symbol |
| Mirror form | ∓ Minus-or-Plus Sign (U+2213) |
The ± sign entered mathematical use in the 16th and 17th centuries as a compact way to express that a quantity could take either of two values without writing out both cases separately. It became indispensable once the quadratic formula was standardized in its modern form — x = (-b ± √(b² - 4ac)) / 2a — where a single ± communicates that there are exactly two roots.
Unlike most math operators, which live in Unicode's dedicated Mathematical Operators block, ± was encoded early enough (in the Latin-1 character set that predates full Unicode) that it sits in the Latin-1 Supplement block alongside ordinary accented letters — a reflection of how commonly it was needed in general typesetting, not just specialist math texts.
| Platform | Works? |
|---|---|
| Instagram bio / caption | Yes |
| Discord | Yes |
| TikTok display name | Yes |
| Yes | |
| Roblox username | No — letters, numbers, underscore only |
| PlayStation Network / Xbox Live gamertag | No — alphanumeric only |
| Method | Input |
|---|---|
| Windows Alt code | Alt+0177 |
| Mac | Option+Shift+= |
| HTML entity | ± or ± |
| CSS content | content: "\00B1" |
| LaTeX | \pm |
± is one of dozens of operators, Greek letters, and set-theory symbols in the full math symbols library.
Browse Math Symbols →± shows that a value could be either higher or lower by a stated amount — a margin of error (5% ± 0.2%), a tolerance range in engineering, or one of two solutions to an equation, as in the quadratic formula.
On Windows, hold Alt and type 0177 on the numeric keypad (Alt+0177). On Mac, press Option+Shift+=. In HTML, use the entity ± or ±.
∓ is the mirror of ±, used when two expressions in the same equation need opposite signs — for example writing cos(a∓b) alongside cos(a±b) to show two related identities at once without repeating the whole formula twice.