How to use it
- Type the number of Inches in the first field.
- Read the result in Millimeters. You can also type in the Millimeters field to convert the other way.
- Use the table of common values, or copy the result with one click.
How it works
Formula: mm = in × 25.4
1 in = 25.4 mm, and 1 mm = 0.03937 in.
Results use the exact definitions of both units. The page shows up to 6 decimal places; copy the value for full precision.
Examples
0.5 in in mm
0.5 in = 12.7 mm, using mm = in × 25.4.
1 in in mm
1 in = 25.4 mm, using mm = in × 25.4.
2 in in mm
2 in = 50.8 mm, using mm = in × 25.4.
Frequently asked questions
How do I convert Inches to Millimeters?
Use the formula mm = in × 25.4. For example, 0.5 in = 12.7 mm.
How do I convert Millimeters back to Inches?
Use the reverse formula in = mm × 0.039370079. For example, 1 mm = 0.03937 in.
How accurate is this converter?
It uses the exact legal definitions of the units, so the only rounding is in the number of decimals shown. Copy the result to get the full value.
Privacy
The conversion runs entirely in your browser. Nothing you type is sent anywhere.