Length and Area
mmtomil
Convert millimetres (mm) to mils (mil).
Factor1 mm = 39.37008 mil
Converter
mm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mil
Rendered to 6 significant figures.
Formula
Formula
mil = mm × 39.37008
Multiply any value in millimetres by 39.37008 to obtain the value in mils.
Worked example
Convert 1 mm to mil.
- 01Start with 1 mm.
- 02Multiply by the conversion factor: 1 × 39.37008 = 39.3701 mil.
Result1 mm = 39.3701 mil
Conversion table
| mm | mil |
|---|---|
| 1 | 39.37 |
| 2 | 78.74 |
| 5 | 196.85 |
| 10 | 393.7 |
| 20 | 787.4 |
| 50 | 1968.5 |
| 100 | 3937 |
| 200 | 7874 |
| 500 | 19685 |
| 1000 | 39370 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from mm to mil?
1 mm equals 39.37008 mil. To convert, multiply the value in millimetres by 39.37008.
How do I convert 1 mm to mil?
1 mm = 39.3701 mil. For any value, multiply by 39.37008.
How do I convert mil back to mm?
Divide by the same factor — or equivalently, multiply by 0.0254. So 1 mil = 0.0254 mm.
When would I need to convert millimetre to mil (thousandth of an inch)?
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).