Inches to Millimetres Converter
Convert inches to millimetres instantly — 1 inch = 25.4 millimetres, with every other length unit, a conversion chart, feet + inches and a list mode for many values.
- Your data never leaves your device
- 100% free
- No sign-up
- Works offline after first load
Formula: mm = in × 25.4
| Inches | Millimetres |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
How to convert inches to millimetres
- Type the number of inches.
- Read the result in millimetres — and in every other unit below it.
- Swap, change the precision, convert a whole list or copy and share the result.
About Inches to Millimetres Converter
Convert inches to millimetres as you type. The result appears instantly with the exact formula, and the same value is shown in every other unit of the category at once — so one page answers all related questions.
A conversion chart lists common values, “Convert a list” handles a whole column of numbers, and you can choose the number of decimals or scientific notation. Swap the units with one click, share a link to your conversion, or print it.
Good for
- Everyday conversions for travel, shopping and recipes
- School and science homework
- Work with specifications and measurements
Tip: Type an expression like a whole column of values in “Convert a list” to convert them all at once.
Frequently asked questions
How do I convert inches to millimetres?
Use millimetres = inches × 25.4. For example, 10 inches = 254 millimetres.
Can I convert many values at once?
Yes — choose “Convert a list”, paste one value per line (a spreadsheet column works) and copy all the results.
Can I convert to other units too?
Yes. Pick any units in the From and To lists, or switch the category — length, weight, temperature, volume, area, speed, data and more.
Can it show feet and inches?
Yes — every length is also shown in feet and inches to the nearest 1/16 inch, e.g. 170 cm = 5 ft 6 15/16 in.
What are some common in to mm values?
0.25 in = 6.35 mm, 0.5 in = 12.7 mm, 1 in = 25.4 mm and 2 in = 50.8 mm.