Micrometer (µm)

Metric (SI)Current unit

One millionth of a meter, also called a micron. Typical bacteria are a few micrometers long; a human hair is roughly 70 µm thick.

1 micrometer = 0.000001 meters (exactly).

ValueFromTo

1 micrometer = 0.000001 meters

About the micrometer

Two names, micron and micrometer, have shared this unit for more than a century. The prefix micro- was adopted in 1873 alongside the CGS system, and in 1879 the term micron and the symbol μ were officially accepted for the micrometer when used on its own. That created a clash once SI came along: μ was also the symbol for the prefix micro-. The 13th CGPM revoked micron and its symbol in 1967 to 1968, leaving micrometer and μm as the official name and symbol, though micron lives on in everyday speech.

A micrometer is a thousandth of a millimeter, and it is the natural scale for biology and filtration. A typical red blood cell is 6 to 8 μm across, a bacterium is 1 to 10 μm long, and a fog droplet is around 10 μm. Human hair ranges from about 17 to 181 μm in diameter, and paper is 70 to 180 μm thick. Infrared radiation is measured in micrometers of wavelength, and wool is graded by fibre width. Some American writers keep micron because micrometer also names the caliper-style measuring tool.

Sources: Wikipedia: Micrometre; Wikipedia: Metric prefix

Micrometer conversion chart

1 micrometer expressed in every other length unit:

Unit	1 micrometer
Meters	0.000001
Kilometers	1×10⁻⁹
Centimeters	0.0001
Millimeters	0.001
Inches	0.00003937007874
Feet	0.000003280839895
Yards	0.000001093613298
Miles	6.213711922×10⁻¹⁰
Nanometers	1,000
Nautical Miles	5.399568035×10⁻¹⁰
Pixels (CSS)	0.003779527559
Light-years	1.057000834×10⁻²²
Picometers	1,000,000
Femtometers	1,000,000,000
Decimeters	0.00001
Hectometers	1×10⁻⁸
Decameters	1×10⁻⁷
Thou	0.03937007874
Points	0.002834645669
Picas	0.0002362204724
Twips	0.05669291339
Astronomical Units	6.684587122×10⁻¹⁸
Light-seconds	3.335640952×10⁻¹⁵
Light-minutes	5.559401587×10⁻¹⁷
Light-hours	9.265669311×10⁻¹⁹
Parsecs	3.240779289×10⁻²³
Megaparsecs	3.240779289×10⁻²⁹
Angstroms	10,000
Fathoms	5.468066492×10⁻⁷
Cable Lengths	5.399568035×10⁻⁹
Leagues	2.071237307×10⁻¹⁰
Nautical Leagues	1.799856012×10⁻¹⁰
Furlongs	4.970969538×10⁻⁹
Chains	4.970969538×10⁻⁸
Rods	1.988387815×10⁻⁷
Links	0.000004970969538
Hands	0.000009842519685
Barleycorns	0.0001181102362
Palms	0.00001312335958
Spans	0.000004374453193
Cubits	0.000002187226597
Ells	8.748906387×10⁻⁷
US Survey Feet	0.000003280833333
US Survey Miles	6.213699495×10⁻¹⁰
Stadia	5.208333333×10⁻⁹
Roman Inches	0.0000406504065
Roman Feet	0.000003378378378
Roman Cubits	0.000002252252252
Roman Paces	6.756756757×10⁻⁷
Roman Stadia	5.405405405×10⁻⁹
Roman Miles	6.756756757×10⁻¹⁰
Roman Leagues	4.504504505×10⁻¹⁰
Greek Feet	0.000003125
Royal Cubits	0.000001904761905
Egyptian Palms	0.00001333333333
Egyptian Fingers	0.00005333333333
Khet	1.904761905×10⁻⁸
Biblical Cubits	0.000001851851852
Sabbath Days' Journeys	9.259259259×10⁻¹⁰
Sun	0.000033
Shaku	0.0000033
Ken	5.5×10⁻⁷
Jō	3.3×10⁻⁷
Chō	9.166666667×10⁻⁹
Ri (Japanese)	2.546296296×10⁻¹⁰
Fen (Chinese)	0.0003
Cun (Chinese)	0.00003
Chi (Chinese)	0.000003
Zhang (Chinese)	3×10⁻⁷
Li (Chinese)	2×10⁻⁹
Vershoks	0.00002249718785
Arshins	0.000001406074241
Sazhens	4.686914136×10⁻⁷
Versts	9.373828271×10⁻¹⁰
Lignes	0.000443296
Pouces	0.00003694133333
Pieds Du Roi	0.000003078444444
Toises	5.130740741×10⁻⁷
Lieues	2.56537037×10⁻¹⁰
Varas	0.000001196315349
Leguas	1.794473023×10⁻¹⁰
Wa (Thai)	5×10⁻⁷
Sen (Thai)	2.5×10⁻⁸
Scandinavian Mil	1×10⁻¹⁰

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