Inches to Millimeters Converter
Convert inches (in) to millimeters (mm) instantly. 1 inch = 25.4 millimeters.
How to convert inches to millimeters
mm = in × 25.4
To convert inches to millimeters, multiply the length value by 25.4. One inch (in) is equal to 25.4 millimeters (mm). For quick everyday conversions, the interactive converter above gives you the exact result as you type — no rounding surprises.
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 7 in | 177.8 mm |
| 8 in | 203.2 mm |
| 9 in | 228.6 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
Frequently asked questions
How many millimeters are in 1 inch?
1 inch equals 25.4 millimeters.
How do I convert inches to millimeters?
Multiply the number of inches by 25.4. For example, 8 in × 25.4 = 203.2 mm.
What is 8 inches in millimeters?
8 inches is equal to 203.2 millimeters.
Can I convert millimeters back to inches?
Yes — use our Millimeters to Inches converter, or divide by 25.4.