Convert Micrometers to Millimeters
1 micrometer is 0.001 mm. One micrometer is exactly 0.001 millimeters.
One micrometer is 0.001 millimeters. To convert micrometers to millimeters, multiply by 0.001; to go the other way, divide by 0.001 or multiply by 1000. The factor is exact rather than rounded: it follows from NIST. A millionth of a meter, still widely called a micron.
Factor checked against the defining standard · How we check
- Micrometers × 0.001
1 * 0.0010.001 mm
1 micrometer in every length unit
| Unit | Value | Exact factor |
|---|---|---|
| inches | 0.00003937007874 in | × 0.0000393700787402 |
| feet | 0.000003280839895 ft | × 0.00000328083989501 |
| yards | 0.000001093613298 yd | × 0.00000109361329834 |
| miles | 0.0000000006213711922 mi | × 0.000000000621371192237 |
| millimeters | 0.001 mm | × 0.001 |
| decimetres | 0.00001 dm | × 0.00001 |
| centimeters | 0.0001 cm | × 0.0001 |
| meters | 0.000001 m | × 0.000001 |
| kilometers | 0.000000001 km | × 0.000000001 |
| nautical miles | 0.0000000005399568035 nmi | × 0.000000000539956803456 |
| micrometers (as entered) | 1 µm | — |
| nanometers | 1,000 nm | × 1,000 |
| thou | 0.03937007874 thou | × 0.0393700787402 |
Factors are entered by hand from NIST rather than derived from a units library, so the ones that terminate are exact rather than rounded.
The same converter answers this pair however it is written: micrometres to millimetres is the British spelling of the same units — the metre and the litre are spelled that way outside the United States and the quantity does not change.
How do you convert micrometers to millimeters? The converter and the working
- 1.Take the measurement in micrometers.
- 2.Multiply by 0.001 — that is how many millimeters fit in one micrometer.
- 3.To go back the other way, divide by 0.001, or multiply by 1000.
Worked example: 25 micrometers to millimeters
- Formula
- µm × 0.001 = mm
- Arithmetic
- 25 × 0.001 = 0.03 mm
- Answer
- 25 µm = 0.03 mm
The factor is exact, so this figure is exact too — only the display is rounded.
Micrometers to millimeters conversion table
| Micrometers | Millimeters |
|---|---|
| 1 µm | 0.001 mm |
| 2 µm | 0.002 mm |
| 3 µm | 0.003 mm |
| 4 µm | 0.004 mm |
| 5 µm | 0.01 mm |
| 6 µm | 0.01 mm |
| 7 µm | 0.01 mm |
| 8 µm | 0.01 mm |
| 9 µm | 0.01 mm |
| 10 µm | 0.01 mm |
| 12 µm | 0.01 mm |
| 15 µm | 0.02 mm |
| 20 µm | 0.02 mm |
| 25 µm | 0.03 mm |
| 50 µm | 0.05 mm |
| 100 µm | 0.1 mm |
| 200 µm | 0.2 mm |
| 300 µm | 0.3 mm |
| 500 µm | 0.5 mm |
| 1000 µm | 1 mm |
| 2000 µm | 2 mm |
| 5000 µm | 5 mm |
| 10000 µm | 10 mm |
What is a micrometer?
A millionth of a meter, still widely called a micron. Machining tolerances, filter ratings and cell diameters are all quoted here.
What is a millimeter?
One thousandth of a meter. The working unit of metric engineering drawings, which avoid decimals by using it throughout.
How many millimeters are in a micrometer?
One micrometer is 0.001 millimeters, exactly. Going the other way, one millimeter is 1000 micrometers. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every length unit here
The whole group — 13 units with their symbols and the size of each one in meters — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to a micrometer.
Source: NIST — international yard and pound agreement (inch = 25.4 mm exactly)
Cite this page
- APA
- Rule Calculator. (2026). Convert Micrometers to millimeters. Rule Calculator. https://rulecalculators.com/convert/micrometer-to-millimeter
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- "Convert Micrometers to millimeters." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/micrometer-to-millimeter.
- Chicago
- Rule Calculator. "Convert Micrometers to millimeters." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/micrometer-to-millimeter.
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Questions people actually ask
- How many millimeters are in a micrometer?
- 0.001. One thousandth of a meter. The working unit of metric engineering drawings, which avoid decimals by using it throughout.
- How do I convert millimeters back to micrometers?
- Divide by 0.001, or multiply by 1000 — they are the same operation.
Other length conversions
Millimeters to micrometers — the same conversion the other way.