Millimeters to Inches Converter
Convert millimeters to inches instantly. Type a value, change either unit, or press swap to go the other way. 1 millimeter = 0.039370079 inches.
1 millimeter = 0.039370079 inches
How to convert millimeters to inches
inches = millimeters × 0.0393700787
To convert millimeters to inches, multiply the value by 0.0393700787. To go back from inches to millimeters, divide by the same number (or multiply by 25.4).
Worked examples
- 5 mm: 5 × 0.0393700787 = 0.19685039 in
- 6.35 mm: 6.35 × 0.0393700787 = 0.25 in
- 10 mm: 10 × 0.0393700787 = 0.39370079 in
Divide millimeters by 25 for a quick estimate; the exact divisor is 25.4. So 50 mm is almost exactly 2 inches.
Millimeters to Inches conversion table
Millimeters to Inches
| mm | in |
|---|---|
| 1 | 0.039370079 |
| 3 | 0.11811024 |
| 5 | 0.19685039 |
| 6.35 | 0.25 |
| 10 | 0.39370079 |
| 12 | 0.47244094 |
| 25.4 | 1 |
| 50 | 1.9685039 |
| 100 | 3.9370079 |
| 250 | 9.8425197 |
Inches to Millimeters
| in | mm |
|---|---|
| 1 | 25.4 |
| 3 | 76.2 |
| 5 | 127 |
| 6.35 | 161.29 |
| 10 | 254 |
| 12 | 304.8 |
| 25.4 | 645.16 |
| 50 | 1,270 |
| 100 | 2,540 |
| 250 | 6,350 |
Distance equivalents
See how one millimeter and one inch compare with every other distance unit on the site.
1 millimeter equals
| Unit | Value |
|---|---|
| centimeters (cm) | 0.1 |
| meters (m) | 0.001 |
| kilometers (km) | 1 × 10-6 |
| inches (in) | 0.03937008 |
| feet (ft) | 0.00328084 |
| yards (yd) | 0.001093613 |
| miles (mi) | 6.213712 × 10-7 |
| nautical miles (nmi) | 5.399568 × 10-7 |
1 inch equals
| Unit | Value |
|---|---|
| millimeters (mm) | 25.4 |
| centimeters (cm) | 2.54 |
| meters (m) | 0.0254 |
| kilometers (km) | 0.0000254 |
| feet (ft) | 0.08333333 |
| yards (yd) | 0.02777778 |
| miles (mi) | 0.0000157828 |
| nautical miles (nmi) | 0.0000137149 |
When you need to convert millimeters to inches
Screw and bolt sizes, drill bits, lens focal lengths, rainfall and sheet thickness are specified in millimeters, but many tools, plans and parts catalogues in North America use inches. Converting precisely stops you buying the wrong fastener or bit.
About the units
Millimeter (mm)
A millimeter is one thousandth of a meter. It is used for precise measurements such as screw sizes, paper thickness and rainfall.
Inch (in)
An inch is defined as exactly 25.4 millimeters. It is used for screen sizes, tire and pipe sizes, and for person height in the United States.
Frequently asked questions
How do I convert millimeters to inches?
Multiply the number of millimeters by 0.0393700787. For example, 10 millimeters × 0.0393700787 = 0.3937007874 inches.
How many inches are in one millimeter?
There are 0.0393700787 inches in one millimeter.
How many millimeters are in one inch?
There are 25.4 millimeters in one inch.
What is 1/4 inch and 1/8 inch in millimeters?
1/4 inch is 6.35 mm and 1/8 inch is 3.175 mm. Every inch is exactly 25.4 mm, so multiply the fraction by 25.4.
Can I convert other distance units with this tool?
Yes. Use the From and To drop-downs in the converter to choose any distance unit, or press the swap button to reverse the conversion. All calculations use internationally defined conversion factors.