Math symbols · U+B1

±Plus-minus symbol

Plus or minus, for tolerances and margins of error.

How to type it
Unicode
U+B1
Alt code
Alt+177
HTML
±
Unicode name
Plus-Minus Sign
±
Your font
01 — Origin

Where the Plus-minus symbol comes from

The plus-minus sign appeared in the seventeenth century as a compact way to write two results at once — the quadratic formula being the case that made it indispensable. Its use for measurement tolerance came much later, from engineering drawings.

Tolerances and error bars: 20 ± 0.5 mm, 48% ± 3. In statistics it introduces a confidence interval, in electronics a component rating, and in weather forecasts a temperature range.

Worth knowing
The inverted ∓ is a real and different character. In a formula the two are linked: it means “take the opposite sign to the ± above”.
02 — Codes

Plus-minus symbol codes

Tap any value to copy it. All of them produce the same character — they just belong to different places.

03 — How to type

How to type ± on any keyboard

Pick the route that matches the program in front of you.

Windows
Hold Alt and type 177 on the numeric keypad, then release. Without a keypad, use the Character Map app (search “charmap”).
Mac
Press Control + Command + Space to open the character viewer, then search “plus-minus”. Double-click to insert.
Phone
There is no shortcut on a phone keyboard. Tap the symbol at the top of this page, then long-press in any text field and choose Paste.
Web and code
In HTML write ± or ±. In CSS content: "\00B1". Make sure the page is served as UTF-8 and the raw character works too.
04 — Font support

Will ± actually show up?

We checked 147 fonts installed on a normal machine and counted how many of them contain this character. A symbol missing from a font is drawn as an empty box — the text is still correct, it just cannot be drawn.

97% 143 of 147 fonts

Safe everywhere. This one is in almost every font ever installed, including the defaults on Windows, Mac and Android.

05 — Similar

Symbols people confuse with ±

Lookalikes that are not the same character at all — separate codes, separate fonts, and here they number 8.

× Multiplication SignU+D7 · has its own page ÷ Division SignU+F7 · has its own page
07 — Same block

Math symbols

Operators, set theory, logic, calculus — everything past the number row.

All math symbols →
08 — FAQ

Plus-minus symbol — questions

How do I type the Plus-minus symbol?
On Windows hold Alt and type 177 on the numeric keypad. On Mac open the character viewer with Control + Command + Space and search “Plus-minus”. Or just tap the symbol on this page — it goes straight to your clipboard.
What is the HTML code for ±?
Write it as ± or ± in HTML, \00B1 in CSS content, and \u00B1 in JavaScript. All four produce the same character.
Is ± an emoji?
No. ± is a text character — it takes the colour of the text around it and works in usernames, filenames and documents. An emoji is replaced by a colour picture and is sometimes stripped by forms and systems.
Why does ± show as a box on some devices?
Because that font has no drawing for this character. We checked 147 fonts on a normal machine and 143 of them include it. The character itself is always correct; only the drawing is missing.