Millimetres to Inches Converter
Type a number to convert millimetres to inches. The result updates as you type, and you can swap the units to convert back.
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The formula
inches = millimetres x 0.03937
How to convert millimetres to inches
To convert millimetres to inches, multiply by 0.03937. One millimetre equals 0.03937 inches, and one inch equals 25.4 millimetres.
A worked example
12 millimetres is 0.47244 inches.
Quick conversion table
| Millimetres | Inches |
|---|---|
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 5 mm | 0.19685 in |
| 6 mm | 0.23622 in |
| 8 mm | 0.31496 in |
| 10 mm | 0.3937 in |
| 12 mm | 0.47244 in |
| 15 mm | 0.59055 in |
| 20 mm | 0.7874 in |
| 25 mm | 0.98425 in |
| 30 mm | 1.1811 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.937 in |
And the other way: inches to millimetres
| Inches | Millimetres |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 4 in | 101.6 mm |
| 5 in | 127 mm |
| 6 in | 152.4 mm |
| 8 in | 203.2 mm |
| 10 in | 254 mm |
| 12 in | 304.8 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 24 in | 609.6 mm |
| 30 in | 762 mm |
| 36 in | 914.4 mm |
| 48 in | 1,219.2 mm |
| 60 in | 1,524 mm |
| 72 in | 1,828.8 mm |
When you will need it
Drill bits, bolts, camera lenses and rainfall are often given in millimetres, while workshops in the US still think in inches.
There are 25.4 millimetres in an inch, so 25 mm is just short of an inch.
Millimetres to Inches Converter: frequently asked questions
How many inches are in one millimetre?
One millimetre is 0.03937 inches.
How many millimetres are in one inch?
One inch is 25.4 millimetres.
Is this millimetres to inches conversion exact?
The factor is exact where the units are defined that way, and we show the result rounded for readability.
How exact is the conversion?
It uses the internationally agreed definitions, and rounds only the number you see.
Is what I enter in this converter saved or sent anywhere?
No. The calculation runs in your browser, so what you enter is not sent to our servers. We only count, anonymously, whether a tool ran successfully.
Is this converter free to use?
Yes. It is free, needs no sign-up and has no usage limit.
Last reviewed: October 3, 2026