1 in equals 25.4 mm. To convert Inch to Millimeter, multiply the value by 25.4; divide by 25.4 to convert back. Enter any number above and the result appears instantly — free and entirely in your browser.
How do you convert Inch to Millimeter?
The conversion formula is mm = in × 25.4. The conversion factor is fixed by definition, so the result is always exact.
Inch to Millimeter conversion table
| in | mm |
|---|---|
| 1 in | 25.4 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 50 in | 1,270 mm |
| 100 in | 2,540 mm |
What is Inch (in)?
The inch (in) is an imperial length unit defined as exactly 2.54 cm. It is used in the US and UK for screen sizes, body height and DIY measurements.
What is Millimeter (mm)?
The millimetre (mm) is one thousandth of a metre, the smallest common metric length unit. It is used for rainfall, screw sizes and material thickness.
Why convert Inch to Millimeter?
Most of the world measures length in metres and centimetres, while the US and UK also use inches, feet and miles. Converting between metric and imperial is a daily need for travel, DIY and online shopping.
By the 1959 international agreement, the inch is exactly 2.54 cm and the foot exactly 0.3048 m. So 1 metre = 3.2808 feet and 1 kilometre = 0.6214 miles.
How to convert Inch to Millimeter
- Enter the value in Inch into the left field of the converter.
- Read the result in Millimeter instantly in the right field — it updates automatically.
- Use the swap button to reverse the direction (Millimeter to Inch).
The converter runs entirely in your browser: no uploads, no queue, no limits. You can even use it offline.