Inches to Millimeters Converter
Convert inches (in) to millimeters (mm)
Result
25.4 mm
Millimeters
1 in = 25.4 mm
1 in in other units
- 1Enter a valueType the number to convert
- 2Pick the unitsChoose what to convert from and to
- 3Read the resultSee it in every other unit too
How to convert inches to millimeters
One inch equals 25.4 millimeters, so multiply the number of inches by 25.4.
mm = in × 25.4
1 in = 25.4 mm · 1 mm = 0.03937008 in
Worked example
To convert 5 inches to millimeters: 5 in × 25.4 = 127 mm.
About inches (in)
An inch is exactly 2.54 cm. It is used for screen sizes, pipe sizes, and lengths in the US and UK.
About millimeters (mm)
A millimeter is one thousandth of a metre. Rain, screen sizes and engineering drawings are often measured in millimetres.
More conversions
Inches to other units
Frequently asked questions
How many millimeters are in one inch?
One inch equals 25.4 millimeters.
How many inches are in one millimeter?
One millimeter equals 0.03937008 inches.
How do I convert inches to millimeters?
Use the formula mm = in × 25.4. For example, 5 in × 25.4 = 127 mm.