Mu Symbol μ — Copy, Paste and How to Type It

Q: How do I type the mu symbol on a keyboard?

On Windows, press Win + . → Symbols → Greek, or in Microsoft Word type 03BC and press Alt + X. On a Mac, switch to the Greek keyboard and press M (Shift + M for the capital). Or simply copy it from the top of this page.

Q: What is the LaTeX command for mu?

Use \mu for lowercase μ, inside math mode. There is no \Mu command for the capital: it looks identical to the Latin M, so you type M.

Q: What is the Unicode and HTML code for mu?

Lowercase μ is U+03BC, written in HTML as μ or μ. Capital Μ is U+039C, written Μ or Μ.

Q: What is the Alt code for μ?

There is no classic Alt code for the Greek letter μ. Alt + 230 and Alt + 0181 both type the micro sign µ (U+00B5), which looks the same. For the true letter, copy it from this page, use Win + . → Symbols → Greek, or in Word type 03BC and press Alt + X.

The mu symbol is the 12th letter of the Greek alphabet, written μ in lowercase and Μ in uppercase. It is pronounced /mjuː/ (“MEW”). Click a symbol to copy it.

Mu is unusual because three different characters look almost identical — and picking the wrong one breaks unit conversions, formulas and data imports. Below you get all three, ready to copy, with the codes you need for Windows, Mac, LaTeX and HTML.

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Copy the mu symbol

Greek small letter mu U+03BC · The lowercase letter

Greek capital letter Mu U+039C · The uppercase letter

Micro sign U+00B5 · Unit prefixes — µm, µg, µL, µF, µs. What Option + M and Alt + 0181 type.

Dashed boxes are look-alikes that are not the Greek letter — listed so you can tell them apart.

μ vs µ — these are two different characters

Look closely: these two glyphs render almost identically, but they are separate Unicode code points with different histories and different correct uses.

Character	Unicode name	Code point	HTML	Use it for
μ	Greek small letter mu	U+03BC	`μ`	The letter itself — statistics, physics, mathematics
Μ	Greek capital letter Mu	U+039C	`Μ`	The uppercase form
µ	Micro sign	U+00B5	`µ`	Unit prefixes — µm, µg, µL, µF, µs

Why do two exist? The micro sign came from the ISO Latin-1 character set (1987), where it stood in for the Greek letter in scientific text. When Unicode was designed, both were kept so that old documents could be converted without changing a single character — and both are still in daily use.

The practical rule: use μ (U+03BC) when it is a variable in a formula, and µ (U+00B5) when it is the “micro” prefix in front of a unit. If you only care how it looks, either works — modern fonts draw them the same. If the text will be parsed, compared or searched, the distinction matters: µm and μm are not equal strings, so string comparisons, sorting and database filters will treat them as different. (Unicode compatibility normalisation, NFKC, does convert µ to μ — but plain NFC does not.)

On a Mac, Option + M gives you µ (U+00B5) — the micro sign, not the letter. The same is true on Windows: Alt + 230 and Alt + 0181 both type the micro sign. To type the actual letter, use a Greek keyboard and press M, or copy it from this page.

In LaTeX, \mu in math mode is the letter μ. For the micro prefix use \textmu (textcomp) in text, \upmu (upgreek) for an upright μ in math, or — best — the siunitx package: \si{\micro\metre}.

Not sure which Greek letter you need? See all 24 Greek symbols with codes.

Mu codes — Unicode, HTML, LaTeX and Alt codes

Char	Unicode	HTML entity	HTML decimal	HTML hex	CSS	JavaScript	LaTeX	Windows	Mac
μ	`U+03BC`	`μ`	`μ`	`μ`	`\03BC`	`\u03BC`	`\mu`	`03BC` then `Alt + X` (Word)	Greek keyboard `M`
Μ	`U+039C`	`Μ`	`Μ`	`Μ`	`\039C`	`\u039C`	`M (no \Mu command)`	`039C` then `Alt + X` (Word)	Greek keyboard `Shift + M`
µ	`U+00B5`	`µ`	`µ`	`µ`	`\00B5`	`\u00B5`	`\textmu`	`Alt + 230 or Alt + 0181`	`Option + M`

Need the characters without any explanation? Open the Greek letters copy-paste sheet.

How to type the mu symbol

Windows

Fastest: press Win + . to open the emoji panel, choose the Symbols tab (Ω), then Greek.
There is no classic Alt code for mu — the old DOS code page only included a handful of Greek letters (α Γ π Σ σ τ Φ Θ Ω δ φ ε). Use one of the other methods.
Microsoft Word: type 03BC and press Alt + X for μ; 039C then Alt + X for Μ. Word converts it in place.

Mac

Add the Greek keyboard in System Settings → Keyboard → Input Sources, then M types μ and Shift + M types Μ.
Option + M on the standard keyboard types µ (Micro sign, U+00B5).
Or open the Character Viewer with Ctrl + Cmd + Space and search “mu”.

iPhone and Android

iOS: Settings → General → Keyboard → Keyboards → Add New Keyboard → Greek. Tap the globe key to switch.
Android (Gboard): Settings → Languages → Add keyboard → Greek.
Or copy the character from the top of this page.

LaTeX

\mu — lowercase μ in math mode
M or \mathrm{M} — capital Μ (there is no \Mu)
\textmu — µ (micro sign)

HTML, CSS and code

HTML: μ or μ or μ
CSS: content: "\03BC";
JavaScript / JSON: "\u03BC" — Python: "\u03bc"
In source code, prefer the escape over the pasted glyph — it survives every file encoding.

Full typing guide for every platform, including Linux and Google Docs → how to type Greek letters.

What does mu mean?

Statistics

μ — the population mean. The sample mean is x̄, and the sample standard deviation is s while the population version is σ. A paper reporting “μ = 12.4, σ = 2.1” is describing the whole population, not a sample.

Physics

μ_s, μ_k — coefficients of static and kinetic friction
μ₀ — the vacuum permeability, about 4π × 10⁻⁷ H/m; μ — magnetic permeability
μ = m₁m₂ / (m₁ + m₂) — reduced mass
μ — linear density, mass per unit length
μ — the muon, originally called the “mu meson”

Chemistry

μ — chemical potential
μ- prefix — a bridging ligand in coordination chemistry, as in μ-oxo

Mathematics

μ(n) — the Möbius function
μ — a measure in analysis and probability theory

Units

µ — the prefix micro, one millionth (10⁻⁶): µm, µs, µF, µg, µL. Strictly this is the micro sign µ (U+00B5), though it renders identically to the letter.

Mu at a glance

Position: 12th of 24
Uppercase / lowercase: Μ μ
Greek name: μι
Pronunciation: /mjuː/
Numeric value: 40
Became: Latin M and Cyrillic М

Frequently asked questions

What is the mu symbol?

Mu (Μ μ) is the 12th letter of the Greek alphabet, pronounced /mjuː/ (“MEW”). It is most often used for mean, micro, coefficient of friction.

How do I type the mu symbol on a keyboard?

On Windows, press Win + . → Symbols → Greek, or in Microsoft Word type 03BC and press Alt + X. On a Mac, switch to the Greek keyboard and press M (Shift + M for the capital). Or simply copy it from the top of this page.

What is the LaTeX command for mu?

Use \mu for lowercase μ, inside math mode. There is no \Mu command for the capital: it looks identical to the Latin M, so you type M.

What is the Unicode and HTML code for mu?

Lowercase μ is U+03BC, written in HTML as μ or μ. Capital Μ is U+039C, written Μ or Μ.

Is µ the same as μ?

No. μ is U+03BC, the Greek letter mu. µ is U+00B5, the micro sign inherited from Latin-1. They look identical in modern fonts but are different characters, and “µm” does not equal “μm” in a string comparison.

What is the Alt code for μ?

There is no classic Alt code for the Greek letter μ. Alt + 230 and Alt + 0181 both type the micro sign µ (U+00B5), which looks the same. For the true letter, copy it from this page, use Win + . → Symbols → Greek, or in Word type 03BC and press Alt + X.

What does μ mean in statistics?

μ is the population mean. The sample mean is x̄ — so a formula using μ describes an entire population, while one using x̄ describes a sample drawn from it.

Is there a capital mu symbol?

Yes, Μ (U+039C). It looks exactly like the Latin capital M, has no LaTeX command, and is typed with Shift + M on a Greek keyboard.

Why is mu pronounced “mew”?

The Greek name of the letter is μι, pronounced “mee” in modern Greek and conventionally “mew” (/mjuː/) in English. That is why it is sometimes written “mew”. (Mew is also a Pokémon — this page is about the Greek letter.)

← See all 24 Greek symbols