Convert Inches to Millimeters
Inches to Millimeters conversion table
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 25 in | 635 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
| 200 in | 5080 mm |
| 500 in | 12700 mm |
| 1000 in | 25400 mm |
How to convert inches to millimeters
The in-to-mm conversion appears often when working with length data across different unit systems. Length conversions are essential in construction, travel planning, science, and everyday measurements when switching between metric and imperial systems.
To convert, multiply the inches value by 25.4. Written as an equation: mm = in × 25.4.
One inches equals approximately 25.4 mm. This means you can multiply any in value by 25.4 to get the equivalent in mm.
Worked example: 10 in = 254 mm. Enter your own value in the converter above for instant results.
Common mistake: A frequent mistake is confusing metric and imperial symbols — for example, mixing up centimeters with inches when reading product dimensions online.
Bookmark this page for quick in to mm conversions, or use the swap button to reverse the direction and convert mm back to in.
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Frequently asked questions
1 in equals 25.4 mm.
Multiply the inches value by 25.4.
10 in = 254 mm.