How to convert millimeters to inches
- Take the value in millimeters.
- Use the formula inches = millimeters ÷ 25.4.
- For example, 25.4 mm is 1 in.
About millimeters and inches
An inch is defined as exactly 25.4 millimeters, so divide millimeters by 25.4 to get inches. One millimeter is 0.03937 inches, a bit less than 1/25 of an inch. For a quick estimate divide by 25, which comes out about 1.6% high.
Millimeters are the standard unit on engineering drawings, bolts, drill bits and product specs in most of the world, while US tools, hardware and tape measures work in inches and fractions of an inch.
Examples
- 25.4 mm (one inch) is 1 in
- 3.5 mm (a standard headphone jack) is 0.138 in
- 85.6 mm (the long side of a credit card) is 3.37 in
- 297 mm (the long side of an A4 sheet) is 11.69 in
Millimeters to inches chart
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 | 0.0394 |
| 2 | 0.0787 |
| 3 | 0.118 |
| 4 | 0.157 |
| 5 | 0.197 |
| 6 | 0.236 |
| 8 | 0.315 |
| 10 | 0.394 |
| 12 | 0.472 |
| 15 | 0.591 |
| 20 | 0.787 |
| 25 | 0.984 |
| 25.4 | 1 |
| 30 | 1.18 |
| Millimeters (mm) | Inches (in) |
|---|---|
| 40 | 1.57 |
| 50 | 1.97 |
| 60 | 2.36 |
| 70 | 2.76 |
| 75 | 2.95 |
| 80 | 3.15 |
| 90 | 3.54 |
| 100 | 3.94 |
| 150 | 5.91 |
| 200 | 7.87 |
| 250 | 9.84 |
| 300 | 11.81 |
| 500 | 19.69 |
| 1,000 | 39.37 |