Length and Area
μmtomm
Convert micrometres (μm) to millimetres (mm).
Factor1 μm = 0.001 mm
Converter
μm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mm
Rendered to 6 significant figures.
Formula
Formula
mm = μm × 0.001
Multiply any value in micrometres by 0.001 to obtain the value in millimetres.
Worked example
Convert 1000 μm to mm.
- 01Start with 1000 μm.
- 02Multiply by the conversion factor: 1000 × 0.001 = 1 mm.
Result1000 μm = 1 mm
Conversion table
| μm | mm |
|---|---|
| 1 | 0.001 |
| 2 | 0.002 |
| 5 | 0.005 |
| 10 | 0.01 |
| 20 | 0.02 |
| 50 | 0.05 |
| 100 | 0.1 |
| 200 | 0.2 |
| 500 | 0.5 |
| 1000 | 1 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from μm to mm?
1 μm equals 0.001 mm. To convert, multiply the value in micrometres by 0.001.
How do I convert 1 μm to mm?
1 μm = 0.001 mm. For any value, multiply by 0.001.
How do I convert mm back to μm?
Divide by the same factor — or equivalently, multiply by 1000. So 1 mm = 1000 μm.
When would I need to convert micrometre to millimetre?
Length conversions appear in piping, layout, and mechanical drawings — particularly when reconciling imperial fittings or instrument lengths with metric plant drawings.
Is the conversion exact?
Yes. Both μm and mm are defined by exact SI relationships, so the displayed factor is exact (any rounding shown is only for display).