Plus Minus Symbol ± Copy & Paste: Math, Science & Keyboard

The plus minus symbol (±) indicates that a value can be either positive or negative. It shows up everywhere in mathematics, science, engineering, and manufacturing tolerances. Every variation is below, ready to copy.

All Plus Minus Symbols

What Does the Plus Minus Symbol Mean?

The ± symbol has two main uses in mathematics and science:

• Two possible values: In the quadratic formula, x = (-b ± sqrt(b²-4ac)) / 2a, the ± means there are two solutions — one using plus, one using minus.
• Tolerance or uncertainty: A measurement written as 25 ± 0.5 mm means the actual value is between 24.5 mm and 25.5 mm.

Common Uses in Real Life

• Manufacturing: Part dimensions like 10.0 ± 0.1 mm specify acceptable tolerance
• Statistics: Survey results like "52% ± 3%" show margin of error
• Physics: Measurement uncertainty in experiments
• Medicine: Blood type notation (A+, A-) sometimes written with ± in genetics
• Temperature: "20 ± 2 degrees" for storage conditions

How to Type the Plus Minus Symbol

Windows

• Hold Alt and type 0177 on the numeric keypad
• Microsoft Word: type 00B1 then press Alt+X
• Or use Character Map: search for "plus minus"

Mac

• Press Option + Shift + = to type ±
• Or use Character Viewer: Control+Command+Space, search "plus minus"

Linux

• Press Ctrl+Shift+U, type 00B1, press Enter

iPhone & Android

• iPhone: Tap the ?123 key, then the #+= key. Long-press the + sign or use a third-party keyboard. Or copy from this page.
• Android: Tap ?123, then =/<. The ± is available on some keyboards, or add a math keyboard. Or copy from above.

LaTeX and HTML Codes

The Quadratic Formula: Why ± Matters

The most famous use of ± is in the quadratic formula. For any equation ax² + bx + c = 0, the solutions are x = (-b ± sqrt(b² - 4ac)) / 2a. The ± exists because squaring a number has two answers: 2² = 4, but (-2)² also equals 4. So the square root of 4 is ±2. Without the ±, you would lose half your solutions.

Plus Minus in Programming

Most programming languages do not have a built-in ± operator. Instead, developers write both cases explicitly. In Python, for example, the quadratic formula would be written as two separate calculations:

• x1 = (-b + math.sqrt(b**2 - 4*a*c)) / (2*a)
• x2 = (-b - math.sqrt(b**2 - 4*a*c)) / (2*a)

The ± symbol is mostly used in documentation, comments, and string output rather than actual code logic.

Related Symbols

• Minus Plus (∓): The opposite of ±, used in expressions where the sign flips
• Approximately (≈): Used when two values are close but not exact
• Equals (=): Exact equality
• Not Equal (≠): Inequality