Millimeter to Inch (mm to in)
Convert mm to in — Length converter
1 millimeter = 0.0393701 inches.
The millimeter (mm) is a small metric length unit; the inch (in) equals exactly 25.4 mm. To convert millimeters to inches, multiply by 0.0393701 — or divide by 25.4.
Millimeters and inches meet most often in engineering, woodworking, 3D printing, and hardware, where precision matters. Because there are 25.4 mm in an inch, a 10 mm bolt head is about 0.394 in.
0.03937008Click to copy
1 mm = 0.03937008 in
Millimeter to Inch formula
1 Millimeter = 0.03937008 in
Worked examples
- 25 mm = 0.98425197 in
- 100 mm = 3.937008 in
Common uses
- Machining, engineering drawings, and tolerances
- Woodworking and 3D-printing dimensions
- Matching metric hardware to imperial tools
Millimeter to Inch conversion table
| Millimeter (mm) | Inch (in) |
|---|---|
| 1 | 0.03937008 |
| 2 | 0.07874016 |
| 3 | 0.11811024 |
| 5 | 0.19685039 |
| 8 | 0.31496063 |
| 10 | 0.39370079 |
| 12 | 0.47244094 |
| 15 | 0.59055118 |
| 20 | 0.78740157 |
| 25 | 0.98425197 |
| 50 | 1.968504 |
| 100 | 3.937008 |
| 250 | 9.84252 |
| 500 | 19.685039 |
| 1000 | 39.370079 |
Frequently asked questions
How many millimeters are in an inch?
One inch equals exactly 25.4 millimeters.
What is 10 mm in inches?
10 mm = 0.3937 in.
What is 25 mm in inches?
25 mm = 0.9843 in (just under one inch).
How do I convert mm to inches quickly?
Divide the millimeters by 25.4. For a rough check, 25 mm is about one inch.