About in to mm
Turn fractional inches (1/8", 1/4", 3/8"…) into millimeters for metric hardware and machining.
To convert, multiply the value in inches by 25.4. For example, 0.75 in = 19.05 mm.
Inches: exactly 2.54 cm. Millimeters: one thousandth of a meter.
Inches to millimeters conversion table
Formula: mm = in × 25.4
| Inches | Millimeters |
|---|---|
| 0.0625 in | 1.5875 mm |
| 0.125 in | 3.175 mm |
| 0.25 in | 6.35 mm |
| 0.375 in | 9.525 mm |
| 0.5 in | 12.7 mm |
| 0.625 in | 15.875 mm |
| 0.75 in | 19.05 mm |
| 1 in | 25.4 mm |
| 1.5 in | 38.1 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
Values rounded to 6 significant figures.
How to do it
- 1
Type a value in inches in the converter above (it is preset to in → mm).
- 2
Read the result instantly; tap Swap units to convert the other way.
- 3
Use the table for common values or the formula mm = in × 25.4 to convert by hand.