Convert Inch (in) to Millimeter (mm) instantly. Enter any value — result updates live.
Converting Inch to Millimeter is a common length conversion. One inch (in) equals 25.4 millimeter (mm). Inches are used for screen sizes, pipe diameters, and small measurements in the US and UK.
This conversion is commonly needed for athletics and sports measurements, shipping and package dimensions, textile and fabric cutting. Millimeters are used in engineering, manufacturing, and medical contexts where precision matters.
To put inch in perspective: a standard pizza (12–14 in). In millimeter, common references include the thickness of a credit card (about 0.76 mm).
The inch was traditionally defined as the width of a man's thumb, and later as three barleycorns laid end to end.
The millimeter is the base unit for precision engineering — most manufacturing tolerances worldwide are specified in millimeters or fractions of one.
People frequently convert between inch and millimeter for:
| Inch (in) | Millimeter (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 30 in | 762 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
| 200 in | 5,080 mm |
| 500 in | 13,000 mm |
| 1000 in | 25,000 mm |