Micrometer Conversion Calculator — µm to nm, mm, inches, mils
Convert a length in micrometres (µm, microns) to nanometres, millimetres, metres, inches, mils (thou), and angstroms in one step. All conversions use exact SI and international-inch definitions.
µm
1 µm = 1000 nm exactly
- 1
Conversion factor
1 µm = 1000 nmExact by SI definition: 1 µm = 10⁻⁶ m, 1 nm = 10⁻⁹ m. - 2
Nanometres
100 × 1000 = 100,000
How does this calculator work?
1 µm = 1000 nm = 0.001 mm = 10⁻⁶ m = 1/25400 in ≈ 0.03937 mil = 10000 Å. Typical objects: bacteria ~1 µm, red blood cells ~7 µm, human hair ~70 µm. All conversions are exact via SI and international-inch (25.4 mm) definitions.
Formula
How this is calculated
The micrometre (µm), also called the micron, is one millionth of a metre (10⁻⁶ m). It sits between the nanometre (10⁻⁹ m) and the millimetre (10⁻³ m), making it the natural unit for biological cells, thin films, optical fibres, and precision machining tolerances.
All conversions in this calculator follow from two exact definitions. The metre-based chain: 1 µm = 10⁻³ mm = 10⁻⁴ cm = 10⁻⁶ m = 1000 nm = 10000 Å (1 angstrom = 10⁻¹⁰ m). The inch-based chain uses the international inch definition of exactly 25.4 mm, so 1 inch = 25 400 µm and 1 mil (thousandth of an inch) = 25.4 µm — both exact.
Biological reference points: a typical bacterium (E. coli) is 1–4 µm long; a human red blood cell is about 6–8 µm in diameter; a human hair is 50–100 µm wide; the unaided eye resolves roughly 100 µm. Visible-light wavelengths are 0.4–0.7 µm (400–700 nm). Modern silicon chips have feature sizes well below 0.01 µm (10 nm). The scale diagram is shown when the input is between 0 and 500 µm.
Frequently asked questions
Divide by 1000: mm = µm / 1000. Equivalently, move the decimal point three places to the left. Examples: 500 µm = 0.500 mm; 25 µm = 0.025 mm; 1 µm = 0.001 mm.
Divide by 25.4: mils = µm / 25.4. This is exact because 1 inch = 25.4 mm and 1 mil = 0.001 inch = 25.4 µm. Examples: 254 µm = 10 mils; 25.4 µm = 1 mil; 100 µm ≈ 3.937 mils.
"Micron" is the informal name for the micrometre (µm). It was the official name until 1967, when SI standardised "micrometre". Both mean exactly 10⁻⁶ m. In biology, medicine, and industry the two names are used interchangeably.
Also known as
TG we-Calculate Editorial Team. (2026). Micrometer Conversion Calculator — µm to nm, mm, inches, mils [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/micrometer-conversion-calculator
TG we-Calculate Editorial Team. "Micrometer Conversion Calculator — µm to nm, mm, inches, mils." TG we-Calculate. 2026. https://we-calculate.com/calculator/micrometer-conversion-calculator.
TG we-Calculate Editorial Team, "Micrometer Conversion Calculator — µm to nm, mm, inches, mils," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/micrometer-conversion-calculator
@misc{wecalculate_micrometer_conversion_calculator, title = {Micrometer Conversion Calculator — µm to nm, mm, inches, mils}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/micrometer-conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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