Length and Area
mmtoμin
Convert millimetres (mm) to microinches (μin).
Factor1 mm = 39370.08 μin
Converter
mm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
μin
Rendered to 6 significant figures.
Formula
Formula
μin = mm × 39370.08
Multiply any value in millimetres by 39370.08 to obtain the value in microinches.
Worked example
Convert 1 mm to μin.
- 01Start with 1 mm.
- 02Multiply by the conversion factor: 1 × 39370.08 = 39370.1 μin.
Result1 mm = 39370.1 μin
Conversion table
| mm | μin |
|---|---|
| 1 | 39370 |
| 2 | 78740 |
| 5 | 1.9685e+5 |
| 10 | 3.9370e+5 |
| 20 | 7.8740e+5 |
| 50 | 1.9685e+6 |
| 100 | 3.9370e+6 |
| 200 | 7.8740e+6 |
| 500 | 1.9685e+7 |
| 1000 | 3.937e+7 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from mm to μin?
1 mm equals 39370.08 μin. To convert, multiply the value in millimetres by 39370.08.
How do I convert 1 mm to μin?
1 mm = 39370.1 μin. For any value, multiply by 39370.08.
How do I convert μin back to mm?
Divide by the same factor — or equivalently, multiply by 2.54e-5. So 1 μin = 2.54e-5 mm.
When would I need to convert millimetre to microinch?
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?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).