Convert Millimeters to Inches
Translate millimeter precision into fractional inches for engineering drawings, jewelry sizing, watch bands and printer paper.
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1 mm = 0.03937 in
Quick reference
| Millimeters | Inches |
|---|---|
| 1 | 0.039 in |
| 5 | 0.197 in |
| 10 | 0.394 in |
| 25.4 | 1.000 in |
| 50 | 1.969 in |
| 100 | 3.937 in |
Formula
inches = millimeters ÷ 25.4
Frequently asked questions
- How many inches is 25 mm?
- 25 mm is about 0.984 in — just under one inch, which is why 25 mm watch lugs are sometimes labelled as '1 inch'.
- Why use mm instead of cm in engineering?
- Most engineering drawings use millimeters because they avoid decimal points for typical part sizes and match standard tool tolerances.