Convert millimeters to inches
Enter a value in millimeters to convert it to inches.
millimeters to inches reference
| millimeters | inches |
|---|---|
| 1 mm | 0.0394 in |
| 2 mm | 0.0787 in |
| 5 mm | 0.1969 in |
| 10 mm | 0.3937 in |
| 25 mm | 0.9843 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.937 in |
The conversion factor
One millimeter is 0.03937008 inches. So to convert, multiply your figure in millimeters by 0.03937008. To go the other way, multiply inches by 25.4, or use the inches to millimeters converter.
Doing it in your head
For a quick estimate, round the factor: roughly "divide by 25". Use the exact converter above when the number matters.
Where this conversion comes up
Height, distance, DIY measurements, maps, and any spec sheet that mixes metric and imperial.
See the common unit conversions cheat sheet for the factors worth memorising.
Related tools
Frequently asked questions
How many inches are in a millimeter?
1 millimeter = 0.03937 inches.
What is the formula to convert millimeters to inches?
Multiply the number of millimeters by 0.03937008. To go back the other way, multiply inches by 25.4.
What is 10 millimeters in inches?
10 millimeters = 0.3937 inches. The reference table below lists more common values.
Is this converter accurate?
It uses the internationally defined conversion factors and computes at full floating-point precision, then rounds only the displayed result. For everyday purposes it is exact; for legal, engineering or scientific work, confirm the required number of significant figures.
Does it work offline?
Yes. The conversion runs in your browser with no server call, so it keeps working with no connection, and nothing you enter is uploaded.
Last reviewed: September 2026. Figures and formulas are checked against their published sources; see the site's data notes.