Cfaser haarrp.jpg
a 6 μm diameter carbon filament,
compared to 50 μm diameter human hair
Unit information
Unit systemmetric
Unit oflength
Unit conversions
1 μm in ...... is equal to ...
   SI units   1×10−6 m
   Natural units   6.1877×1028 P
1.8897×104 a0
   imperial/US units   3.2808×10−6 ft
 3.9370×10−5 in

The micrometre (International spelling as used by the International Bureau of Weights and Measures;[1] SI symbol: μm) or micrometer (American spelling), also commonly known by the previous name micron, is an SI derived unit of length equaling 1×10−6 metre (SI standard prefix "micro-" = 10−6); that is, one millionth of a metre (or one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch).[1]

The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria,[1] and for grading wool by the diameter of the fibres.[2] The width of a single human hair ranges from approximately 10 to 200 μm. The longest human chromosome is approximately 10 μm in length.


Between 1 μm and 10 μm:

Between 10 μm and 100 μm

  • about 10–12 μm – thickness of plastic wrap (cling wrap)
  • 10 to 55 μm – width of wool fibre[5]
  • 17 to 181 μm – diameter of human hair[6]
  • 70 to 180 μm – thickness of paper
Other Languages
العربية: ميكرومتر
aragonés: Micrometro
asturianu: Micrómetru
azərbaycanca: Mikrometr
Bân-lâm-gú: Bî-bí
беларуская: Мікраметр
беларуская (тарашкевіца)‎: Мікрамэтар
bosanski: Mikrometar
català: Micròmetre
Чӑвашла: Микрометр
čeština: Mikrometr
Ελληνικά: Μικρόμετρο
emiliàn e rumagnòl: Micròmeter
Esperanto: Mikrometro
فارسی: میکرون
français: Micromètre
Frysk: Mikrometer
furlan: Micrometri
Gaeilge: Miocrón
galego: Micrómetro
客家語/Hak-kâ-ngî: Mì-mí
Bahasa Indonesia: Mikrometer (satuan)
íslenska: Míkrómetri
къарачай-малкъар: Μm
ქართული: მიკრომეტრი
қазақша: Микрометр
Kiswahili: Mikromita
kurdî: Mîkrometre
Кыргызча: Микрометр
Latina: Micrometrum
latviešu: Mikrometrs
Lëtzebuergesch: Mikrometer
македонски: Микрометар
Bahasa Melayu: Mikrometer
norsk: Mikrometer
norsk nynorsk: Mikrometer
پنجابی: مائکرون
polski: Mikrometr
русский: Микрометр
Scots: Micrometre
shqip: Mikrometri
Simple English: Micrometre
slovenčina: Mikrometer
slovenščina: Mikrometer
srpskohrvatski / српскохрватски: Mikrometar
svenska: Mikrometer
Türkçe: Mikrometre
українська: Мікрометр
اردو: مائکرون
vèneto: Micròmetro
Tiếng Việt: Micrômét
Winaray: Mikrometro
粵語: 微米
中文: 微米