Inches to Millimeters Converter
1 inch (in) = exactly 25.4 millimeters (mm). 6 inches = 152.4 mm. 12 inches (1 ft) = 304.8 mm.
Inverse conversion
1 millimeter (mm) = 0.0393701 inches. Since 1 inch = 25.4 mm exactly, divide mm by 25.4 to convert.
Formula
Formula
mm = in × 25.4
Worked example
To convert 6 inches to mm, multiply 6 × 25.4. Result: 152.4 mm.
Quick reference table
| in | mm |
|---|---|
| 0.25 | 6.35 |
| 0.5 | 12.7 |
| 1 | 25.4 |
| 2 | 50.8 |
| 4 | 101.6 |
| 6 | 152.4 |
| 12 | 304.8 |
| 24 | 609.6 |
Unit definitions
Inch (in)
The inch (in) equals exactly 25.4 mm by international agreement since 1959.
Millimeter (mm)
The millimeter (mm) is 1/1,000 of a meter. Standard precision unit in metric countries.
Common use cases
- Converting imperial hardware dimensions to metric spec sheets
- 3D printing and CAD: imperial designs to mm
- Photography: sensor sizes in inches to mm
- Plumbing: pipe sizes