Convert Inches to Millimeters
Convert inches to millimeters instantly. Type a value below, check the formula and table, then see how the same in to mm conversion looks as a single line in Notes Calculator.
Inches to Millimeters formula
One inch is 25.4 millimeters, so mm = in × 25.4. For the reverse, multiply millimeters by 0.0393701, or use the Millimeters to Inches converter.
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 | 25.4 |
| 2 | 50.8 |
| 5 | 127 |
| 10 | 254 |
| 20 | 508 |
| 25 | 635 |
| 50 | 1,270 |
| 100 | 2,540 |
| 250 | 6,350 |
| 500 | 12,700 |
| 1,000 | 25,400 |
Inches to Millimeters in Notes Calculator
Notes Calculator is a notepad that does math. Write 100 inches to mm on any line and the answer appears beside it. Change the number and the result follows. The same works with in and as, and with values stored in variables, so a whole estimate can mix inches and millimeters without a separate converter.
| Note | Result |
|---|---|
| 100 inches to mm | 2,540 mm |
| 100 inches in mm | 2,540 mm |
| 10 mm as inches | 0.39 in |
See the unit conversion docs for mixing units in one expression, or open the free web app and try it.
FAQ
Frequently asked questions
- One inch equals 25.4 millimeters. To convert inches to millimeters, multiply by 25.4; to go back, multiply by 0.0393701.
- Type the value, the unit, and the target unit on one line: 100 inches to mm. The keywords to, in, and as all work, and the result updates as you type. You can also keep the value in a variable and convert it later.
- Yes. The converter on this page is free, and Notes Calculator has a free plan for the web, Mac, Windows, Linux, and Android with the same unit conversions built in.
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Notes Calculator is free to start and runs in your browser. Units, currencies, percentages, and variables in one plain-text notepad.
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