Plus Minus Symbol ±: Copy, Meaning and Shortcuts

What Does the Plus or Minus Symbol Mean?

The plus or minus symbol is read as "plus or minus". It is used in two main ways.

1. Two answers at once

The equation x² = 9 has two answers: 3 and −3, because both 3 × 3 and (−3) × (−3) give 9. Instead of writing both, we write x = ±3.

2. A range or tolerance

In science, engineering and manufacturing, no measurement is perfect. A shaft marked 25 ± 0.2 mm is accepted if it is between 24.8 mm and 25.2 mm. A weather report may say a temperature is 32 ± 1 °C. Survey results often add "± 3%" as a margin of error.

The minus-plus sign ∓ is its mirror. It appears in formulas together with ±, where the top sign of one goes with the top sign of the other. For example, cos(A ± B) = cos A cos B ∓ sin A sin B.

Plus Minus Symbol in the Quadratic Formula

The most famous use of ± in school maths is the quadratic formula. For ax² + bx + c = 0:

x = (−b ± √(b² − 4ac)) / 2a

Let us solve x² − 5x + 6 = 0. Here a = 1, b = −5, c = 6.

1. b² − 4ac = 25 − 24 = 1, and √1 = 1.
2. x = (5 ± 1) / 2.
3. Using +: x = 6 / 2 = 3. Using −: x = 4 / 2 = 2.

So the two roots are 3 and 2. The ± sign is what gives us both answers in one line. The root sign is explained on our square root symbol page.

Plus or Minus Symbol Shortcut on Keyboard

Alt+0177 comes from the Windows-1252 table and Alt+241 from the older DOS table. Both normally give ±, but if one fails in an app, try the other. When they cannot find it, many people type a +- symbol or a +/- symbol made from two keys. That is understood in a chat, but in a report the real ± looks far better.

Plus Minus Symbol in Excel and Word

Showing ± in a cell: use Alt+0177, or the formula =UNICHAR(177).

Joining a value and its tolerance: if A2 has 10 and B2 has 0.5, the formula =A2&" ± "&B2 shows 10 ± 0.5. The result is text, so keep the original numbers for calculations.

Adding a + sign before positive numbers: select the cells, press Ctrl+1 to open Format Cells, choose Custom, and type +0;-0;0. Positive values now show as +5, negatives as -5 and zero as 0. This is handy for profit and loss or change columns.

In Word equations: insert an equation with Insert > Equation and type \pm followed by a space; Word changes it to ±.

Plus Symbol, Minus Symbol and the Hyphen

The addition symbol + and the subtraction symbol (also called the subtract symbol) − are the first signs every child learns: 7 + 5 = 12 and 12 − 5 = 7.

• Plus sign + (Alt+43): the + symbol stands for addition, and also the positive symbol, as in +5 °C. It appears in phone numbers with country codes, such as +91 for India, and in blood groups such as O+ (read "O positive").
• Hyphen-minus -: the key next to 0 on your keyboard. Excel, calculators and code use it for subtraction and negative numbers.
• True minus sign − (U+2212): the proper typographic minus. It is the same width as + and sits at the same height, so it looks neater in printed maths. There is no standard Alt code; use 2212 then Alt+X in Word, or copy it here.
• ➕ and ➖: heavy emoji-style signs for chats, posters and buttons.

Do not paste the true minus − into Excel formulas; Excel expects the keyboard hyphen. For more on the short line, see the hyphen symbol page, and for related operations see the multiplication symbol and divide symbol.

Common Mistakes with ±

• Forgetting the second answer: √16 = 4, but the equation x² = 16 gives x = ±4.
• Reading tolerance as a single value: 50 ± 5 g is a range from 45 g to 55 g, not 55 g.
• Using an underlined + made by formatting: it may look right on screen but is lost when copied. Use the real ± character.