How to Type a Plus-Minus Sign
The plus-minus sign (±) indicates a range or tolerance in measurements, engineering specifications, and mathematical expressions. Essential for precision and uncertainty notation.
Last reviewed on April 23, 2026.
Quick Reference
Windows
Hold Alt and type 0177 on the numeric keypad.
Alt + 0177
Mac
Press Option + Shift + =.
Option + Shift + =
Linux
Press Ctrl + Shift + U, type 00B1, press Enter.
Ctrl + Shift + U, 00B1, Enter
HTML
Use the HTML entity ± or numeric ±.
± or ±
Common Uses
The plus-minus symbol is widely used across scientific, engineering, and mathematical contexts to express variation, uncertainty, or dual solutions.
- Engineering tolerances: 100mm ±0.5mm (acceptable range: 99.5mm to 100.5mm)
- Scientific measurements: 25.3°C ±0.2°C (measurement uncertainty)
- Mathematics: x = ±5 (x equals positive or negative 5)
- Statistics: Mean ± standard deviation (68.2 ± 3.4)
- Manufacturing specs: Dimensions with acceptable variance
- Quadratic equations: Solutions using ± in the quadratic formula
Interpretation
The plus-minus sign has two main interpretations depending on context:
1. Range or tolerance: When used with a single value (e.g., 50 ±5), it means the actual value falls between 45 and 55. The ± indicates acceptable deviation from the nominal value.
2. Dual solutions: In mathematics, x = ±3 means x can be either +3 or -3. Both values are valid solutions to the equation.
Technical Details
Unicode: U+00B1
HTML Entity: ±
HTML Decimal: ±
Alt Code (Windows): Alt + 0177
Name: PLUS-MINUS SIGN