About Millimeters to Inches Converter
This converter turns millimeters into inches. One millimeter is 0.0393701 inches. It is free, needs no sign-up and runs in your browser, so nothing you enter is uploaded.
To convert by hand, multiply the number of millimeters by 0.039370079. For example, 10 mm × 0.039370079 = 0.393701 in. To go back, multiply inches by 25.4. For a rough mental estimate, multiply by about 0.039, which is off by about 0.9 percent.
One millimeter is 0.001 m. Every length unit here is defined from the meter: 1 inch is exactly 25.4 mm, 1 foot is exactly 0.3048 m, 1 mile is exactly 1,609.344 m and 1 nautical mile is exactly 1,852 m. The factor on this page is therefore exact, and only the displayed digits are rounded.
How to use Millimeters to Inches Converter
- Choose a group such as Length or Temperature from the Quantity picker. It opens on a worked conversion.
- Type the value you want to convert in the From box. Decimals and negative numbers are fine.
- Pick the unit you have in the From list and the unit you want in the To list. The swap button reverses the pair.
- Read the result in the result card, and use the copy button to put it on your clipboard.
- Set Precision to Auto, or to a fixed number of decimals from 0 to 10, if you need a specific rounding.
- Check the formula line and the chart of common values under the result when you want to see how the number was reached.
Features
- 102 units in 15 groups, from nanometers and light-years to square miles, and from bits to tebibytes. It includes milligrams, UK gallons and pints, cubic meters, feet and inches, degrees and radians, hertz and rpm, and bits per second to MB/s.
- Results update as you type, with a swap button to reverse the pair.
- Precision control: Auto (up to 8 significant digits) or 0 to 10 fixed decimals.
- A copy button for the result.
- The formula and the factor in both directions, shown under the result.
- A chart of common values (1, 2, 5, 10, 20, 25, 50, 75, 100, 250, 500 and 1,000) for the pair you chose.
- Temperature handled with proper offset formulas, plus the UK gas mark oven table.
- Fuel economy handled as an inverse, so US and UK miles per gallon and liters per 100 km convert correctly.
- Bangladesh land units: decimal (shotangsho), katha and bigha.
- Both decimal data units (KB, MB, GB, TB) and binary ones (KiB, MiB, GiB, TiB), clearly labeled.
Millimeters to inches formula
To convert millimeters to inches, multiply the value by 0.039370079.
To go the other way, multiply inches by 25.4, which is the same as dividing by 0.039370079.
in = mm × 0.039370079Worked examples
10 mm gives 0.393701 in
10 × 0.039370079 = 0.393701
20 mm gives 0.787402 in
20 × 0.039370079 = 0.787402
100 mm gives 3.93701 in
100 × 0.039370079 = 3.93701
Millimeters to inches conversion chart
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 | 0.0393701 |
| 2 | 0.0787402 |
| 3 | 0.11811 |
| 4 | 0.15748 |
| 5 | 0.19685 |
| 6 | 0.23622 |
| 8 | 0.314961 |
| 10 | 0.393701 |
| 12 | 0.472441 |
| 15 | 0.590551 |
| 20 | 0.787402 |
| 25 | 0.984252 |
| 30 | 1.1811 |
| 50 | 1.9685 |
| 100 | 3.93701 |
| 500 | 19.685 |
| 1,000 | 39.3701 |
Privacy: how it works
- Every conversion is calculated by code running in your browser tab. The values you type are never sent to Ulkaa or anyone else, and nothing is stored.
- There is no account and no sign-up for this tool, and it costs nothing to use.
Tips
- Use the swap button instead of retyping when you need the reverse conversion.
- For a quick mental check, round the factor: 1 inch is about 2.5 cm, 1 kg is about 2.2 lbs, 1 mile is about 1.6 km.
- Set Precision to 2 decimals for cooking, shopping and travel, and to 6 or more for engineering work.
- Check whether a figure uses US or imperial units before converting volumes, gallons and miles per gallon.
- For land, convert for a rough size, then confirm the area from the deed or survey record.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial and no credit card. Ulkaa Tool does the work with your own device, so there is no server bill to pass on to you.
Do I need an account?
No. There is no sign-up and no login. Open the page and use it. An Ulkaa account is not needed for anything on this tool.
Does it run in my browser?
Yes. Your values are processed by code running in your browser tab, on your own device.
Is my data uploaded?
No. Your values are never sent to Ulkaa or to anyone else. You can check this yourself by watching the Network tab in your browser developer tools while you use the tool.
How many inches are in a millimeter?
One millimeter is 0.0393701 inches.
How many millimeters are in an inch?
One inch is 25.4 millimeters.
How do I convert millimeters to inches by hand?
Multiply the value in millimeters by 0.039370079. For example, 10 mm is 0.393701 in. To reverse it, divide by 0.039370079.
Is the millimeter to inch factor exact?
Yes. Length units are defined from the meter, and 1 millimeter is exactly 0.001 m. The digits you see on this page are rounded for display only.
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