MM to Inches Converter
Convert millimetres to inches in your browser, with a full reference table and the formula behind it. Free, instant, no sign-up.
How to convert millimetres to inches
inches = millimetres × 0.03937
One millimetre is 0.03937 inches, so any conversion is a single multiplication. To go the other way, divide by 0.03937 instead. The converter above is already set to millimetres and inches, so you can type any value and read the answer straight away.
MM to Inches conversion table
Common values, worked out in advance:
| Millimetres (mm) | Inches (in) |
|---|---|
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 3 mm | 0.11811 in |
| 5 mm | 0.19685 in |
| 10 mm | 0.393701 in |
| 15 mm | 0.590551 in |
| 20 mm | 0.787402 in |
| 25 mm | 0.984252 in |
| 30 mm | 1.1811 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.937 in |
The quick mental version
For a rough answer without a calculator, remember that 1 in is about 25.4 mm. That is usually close enough for shopping, travel and DIY, and the converter above gives you the exact figure when it matters.
Related conversions
CM to Inches Inches to CM Feet to Meters Meters to Feet KM to Miles KG to Lbs All Unit Converters
Frequently asked questions
How many inches are in 1 mm?
One mm is 0.03937 in. The table above covers the values people look up most often.
What is the formula to convert millimetres to inches?
inches = millimetres × 0.03937. One millimetre is 0.03937 inches, so any conversion is a single multiplication. To go the other way, divide by 0.03937 instead.
Is this mm to inches converter accurate?
Yes. It uses the exact internationally defined conversion factors and calculates in your browser, so nothing is rounded until the result is displayed.
Can I convert inches back to millimetres here?
Yes. Use the swap button in the converter to reverse the direction, or pick any other pair of units from the two dropdowns.