How to Type a Micro Sign
The micro sign (µ) represents one millionth (10⁻⁶) in the metric system. Essential for scientific measurements, electronics, and precise units like micrometers and microseconds.
Last reviewed on October 3, 2026.
Quick Reference
Windows
Hold Alt and type 0181 on the numeric keypad.
Alt + 0181
Mac
Press Option + M.
Option + M
Linux
Press Ctrl + Shift + U, type 00B5, press Enter.
Ctrl + Shift + U, 00B5, Enter
HTML
Use the HTML entity µ or numeric µ.
µ or µ
Common Uses
The micro symbol is an SI prefix meaning one millionth (10⁻⁶). It appears across scientific, engineering, and technical contexts when expressing very small measurements.
- Length: µm (micrometer, one millionth of a meter) — cell sizes, wavelengths
- Time: µs (microsecond) — computer processing, signal timing
- Volume: µL (microliter) — laboratory measurements, pipettes
- Mass: µg (microgram) — pharmaceutical dosages, trace elements
- Electronics: µF (microfarad) — capacitor values
- Biology: Cell dimensions (10-100 µm), bacterial sizes
Micro Sign vs. Greek Letter Mu
The micro sign (µ) and the Greek lowercase letter mu (μ) look identical but are technically different characters:
- Micro sign (µ): U+00B5, used as a SI prefix for units (µm, µs)
- Greek mu (μ): U+03BC, used in mathematics and physics as a variable
For unit prefixes, use the micro sign (µ). For mathematical variables like coefficient of friction or population mean, use Greek mu (μ).
Metric Prefix Context
The micro prefix in the metric system:
milli (m): 10⁻³ (one thousandth)
micro (µ): 10⁻⁶ (one millionth)
nano (n): 10⁻⁹ (one billionth)
pico (p): 10⁻¹² (one trillionth)
Example: 1 mm = 1,000 µm = 1,000,000 nm
More Ways to Type µ
- Windows (OEM code):
Alt + 230also gives µ in most apps. - Microsoft Word:
00B5then Alt + X for the micro sign, or03BCthen Alt + X for Greek μ. - LaTeX:
\textmuin text,\muin maths; withsiunitx,\microinside a unit, e.g.\qty{5}{\micro\metre}. - Phones: add the Greek keyboard and type m for μ, or long-press u on some keyboards.
Unicode treats µ (U+00B5) as compatible with Greek μ (U+03BC): normalising text with NFKC turns the micro sign into the Greek letter. Search engines and most software therefore treat them as equivalent, but mixing both in one document can break exact-match searches.
Technical Details
Unicode: U+00B5
HTML Entity: µ
HTML Decimal: µ
Alt Code (Windows): Alt + 0181
Name: MICRO SIGN