Convert Micrometers to Millimeters
1 micrometer (µm) equals 0.001 millimeters (mm).
1 µm = 0.001 mm
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk micrometer to millimeter converter to paste a column from Excel.
How to Convert Micrometer to Millimeter
- 1 µm = 0.001 mm
- 1 mm = 1000 µm
- Example: convert 15 µm to mm: 15 µm = 15 × 0.001 mm = 0.015 mm
Formula
mm = µm ÷ 1000
Derivation from SI units:
- 1 µm = 10⁻⁶ m
- 1 mm = 10⁻³ m
- 1 µm = 0.000001 m ÷ 0.001 m per mm = 0.001 mm
Both units are defined exactly, so the factor is exact. Micrometer definition: micrometer; Millimeter definition: millimeter.
Worked examples
- A 50 µm human hair is 0.05 mm thick.
50 µm × 0.001 = 0.05 mm - A PM2.5 particle of 2.5 µm is 0.0025 mm.
2.5 µm × 0.001 = 0.0025 mm
Micrometer to Millimeter conversion table
| Micrometers (µm) | Millimeters (mm) |
|---|---|
| 0.1 µm | 0.0001 mm |
| 0.3 µm | 0.0003 mm |
| 0.5 µm | 0.0005 mm |
| 1 µm | 0.001 mm |
| 2.5 µm | 0.0025 mm |
| 5 µm | 0.005 mm |
| 10 µm | 0.01 mm |
| 20 µm | 0.02 mm |
| 25 µm | 0.025 mm |
| 50 µm | 0.05 mm |
| 75 µm | 0.075 mm |
| 100 µm | 0.1 mm |
| 150 µm | 0.15 mm |
| 200 µm | 0.2 mm |
| 500 µm | 0.5 mm |
| 1000 µm | 1 mm |
Where it's used
Particle sizes, coating thicknesses and tolerances in micrometres (microns) are converted to millimetres for drawings and specifications. Divide by 1000.
Micrometer to other length units
| Conversion | 1 µm equals |
|---|---|
| micrometer to meter | 0.000001 m |
| micrometer to kilometer | 1 × 10⁻⁹ km |
| micrometer to centimeter | 0.0001 cm |
| micrometer to millimeter | 0.001 mm |
| micrometer to nanometer | 1000 nm |
| micrometer to angstrom | 10000 Å |
| micrometer to mile | 6.213711922 × 10⁻¹⁰ mi |
| micrometer to yard | 0.000001093613298 yd |
| micrometer to foot | 0.000003280839895 ft |
| micrometer to inch | 0.00003937007874 in |
| micrometer to mil | 0.03937007874 mil |
| micrometer to nautical mile | 5.399568035 × 10⁻¹⁰ nmi |
Frequently asked questions
Is a micron the same as a micrometer?
Yes. "Micron" is the common name for the micrometre, 1 µm = 0.001 mm.
How many millimeters are in 1 micrometer?
1 µm = 0.001 mm.
How do I convert micrometers to millimeters?
Multiply the value in µm by 0.001, or divide it by 1000. For example, 15 µm × 0.001 = 0.015 mm.
Is the µm to mm conversion exact?
Yes. Both units are defined exactly, and 1 µm is exactly 0.001 mm.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Micrometers to Millimeters. Retrieved October 17, 2026, from https://scientificconverters.com/length/micrometers-to-millimeters/
IEEE
Scientific Converters, "Convert Micrometers to Millimeters," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/length/micrometers-to-millimeters/