Convert Mils to Millimeters
1 mil equals 0.0254 millimeters (mm).
1 mil = 0.0254 mm
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk mil to millimeter converter to paste a column from Excel.
How to Convert Mil to Millimeter
- 1 mil = 0.0254 mm
- 1 mm = 39.37007874 mil
- Example: convert 15 mil to mm: 15 mil = 15 × 0.0254 mm = 0.381 mm
Formula
mm = mil × 0.0254
or mm = mil ÷ 39.37007874016
Derivation from SI units:
- 1 mil = 0.001 in = 25.4 µm (exact)
- 1 mm = 10⁻³ m
- 1 mil = 0.0000254 m ÷ 0.001 m per mm = 0.0254 mm
Both units are defined exactly, so the factor is exact. Mil definition: mil; Millimeter definition: millimeter.
Worked examples
- A 4 mil plastic film is 0.1016 mm thick.
4 mil × 0.0254 = 0.1016 mm - A 10 mil coating is 0.254 mm.
10 mil × 0.0254 = 0.254 mm
Mil to Millimeter conversion table
| Mils (mil) | Millimeters (mm) |
|---|---|
| 0.5 mil | 0.0127 mm |
| 1 mil | 0.0254 mm |
| 1.5 mil | 0.0381 mm |
| 2 mil | 0.0508 mm |
| 3 mil | 0.0762 mm |
| 4 mil | 0.1016 mm |
| 5 mil | 0.127 mm |
| 6 mil | 0.1524 mm |
| 8 mil | 0.2032 mm |
| 10 mil | 0.254 mm |
| 15 mil | 0.381 mm |
| 20 mil | 0.508 mm |
| 40 mil | 1.016 mm |
| 50 mil | 1.27 mm |
| 100 mil | 2.54 mm |
Where it's used
Film, bag and coating thicknesses in mils (thousandths of an inch) are converted to millimetres or microns. 1 mil = 0.0254 mm exactly; it is not a millimetre.
Mil to other length units
| Conversion | 1 mil equals |
|---|---|
| mil to meter | 0.0000254 m |
| mil to kilometer | 2.54 × 10⁻⁸ km |
| mil to centimeter | 0.00254 cm |
| mil to millimeter | 0.0254 mm |
| mil to micrometer | 25.4 µm |
| mil to nanometer | 25400 nm |
| mil to angstrom | 254000 Å |
| mil to mile | 1.578282828 × 10⁻⁸ mi |
| mil to yard | 0.00002777777778 yd |
| mil to foot | 0.00008333333333 ft |
| mil to inch | 0.001 in |
| mil to nautical mile | 1.371490281 × 10⁻⁸ nmi |
Frequently asked questions
Is a mil the same as a millimeter?
No. 1 mil = 0.001 in = 0.0254 mm, about 39 times smaller than a millimetre.
How many millimeters are in 1 mil?
1 mil = 0.0254 mm.
How do I convert mils to millimeters?
Multiply the value in mil by 0.0254, or divide it by 39.37007874. For example, 15 mil × 0.0254 = 0.381 mm.
Is the mil to mm conversion exact?
Yes. Both units are defined exactly, and 1 mil is exactly 0.0254 mm.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "mil (0.001 in)".
- 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 Mils to Millimeters. Retrieved October 17, 2026, from https://scientificconverters.com/length/mils-to-millimeters/
IEEE
Scientific Converters, "Convert Mils to Millimeters," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/length/mils-to-millimeters/