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Micro Symbol (Mu) (µ)

The micro symbol (µ) means 'one millionth' — a micrometre (µm) is a millionth of a metre, far thinner than a hair.

Micro Sign · U+00B5 · Math Symbols

Click the symbol or the button to copy it, then paste it anywhere — documents, messages, bios and code.

Micro Symbol (Mu) codes

Code	Value
Unicode code point	`U+00B5`
Unicode name	`Micro Sign`
HTML named entity	`µ`
HTML decimal	`µ`
HTML hex	`µ`
CSS content code	`\B5`
JavaScript / JSON	`\u00B5`
Windows Alt code	`Alt+0181`
LaTeX	`\mu`

Micro Symbol (Mu) variants (1)

1 related glyphs — click any tile to copy it. Tiles with a page open that symbol's own page.

μGreek Small Letter Mu

Meaning & usage

µ is the SI prefix micro-: stick it in front of a unit and the unit shrinks a million times. It sizes the invisible world — bacteria measured in µm, doses in µg, timing in µs — and appears on medicine labels, camera specs and science writing everywhere. It looks like a small u with a tail because it is really the Greek letter mu (μ); Unicode keeps µ and μ as separate-but-identical twins, and the µ on this page is the one keyboards and Alt+0181 produce.

Examples in use

A human hair is about 70 µm wide
Vitamin D dose: 25 µg
Response time 250 µs

How to type the micro symbol (mu)

Windows

Hold the Alt key and type 0181 on the numeric keypad (Num Lock on), then release Alt. The code is Alt+0181. It also works in Word with the same keys.

Mac

Press Option+M (Mac, US keyboard layout).

iPhone & Android

Most phone keyboards have no built-in key for µ. Open this page on your phone, tap Copy, then paste it into your message or bio. (On Android, Gboard's emoji search finds some symbols by name.)

Linux

Press Ctrl+Shift+U, type 00b5 and press Enter (works in most GTK apps and terminals with IBus). Or copy it from this page.

Frequently asked questions

How do I type µ on a keyboard?

On Windows, hold Alt and type 0181 on the numeric keypad. On a Mac, press Option+M. Or copy µ from this page.

Is µ the same as the Greek letter μ?

They look identical and come from the same letter. Unicode has both: µ (U+00B5) is the micro sign for units, μ (U+03BC) is the Greek small letter mu used in maths and statistics. Either usually displays fine.

What does µ mean in measurements?

It means one millionth (1/1,000,000). So 1 µm = 0.000001 m, and 1 µL is a millionth of a litre.

Why does µ sometimes show as a box or question mark?

The box (called tofu) means the device or font viewing it has no drawing for U+00B5 (Micro Sign). The character itself is fine — try a different font or a newer device, or use one of the variants on this page.

Is the Micro Symbol (Mu) free to use?

Yes. µ is a standard Unicode text character published in the Unicode Character Database. You may use it in personal and commercial documents, designs and products without permission or payment.

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