Length
fractional inches to mm Converter
Convert common inch fractions into millimeters without guessing the decimal first.
Convert inch fractions to mm
Use the whole-inch field for mixed numbers such as 1 3/8 in. 1 inch is exactly 25.4 mm.
How to use this calculator
- Enter the values the calculator asks for.
- Check the instant result and alternate values below it.
- Use the chart and formula to verify common examples.
fractional inches to mm chart
| Fractional inches | Decimal inches | Millimeters |
|---|---|---|
| 1/64 in | 0.01563 in | 0.39687 mm |
| 1/32 in | 0.03125 in | 0.79375 mm |
| 1/16 in | 0.0625 in | 1.5875 mm |
| 1/8 in | 0.125 in | 3.175 mm |
| 1/4 in | 0.25 in | 6.35 mm |
| 1/2 in | 0.5 in | 12.7 mm |
| 1 1/4 in | 1.25 in | 31.75 mm |
| 2 3/8 in | 2.375 in | 60.325 mm |
Formula
mm = (whole inches + numerator / denominator) x 25.4
Source
SI meter definitions and exact international inch, foot, yard, and mile relationships.
Common questions
How does the fractional inches to mm Converter work?
Convert common inch fractions into millimeters without guessing the decimal first.
What formula does this calculator use?
mm = (whole inches + numerator / denominator) x 25.4
Is the result exact?
SI meter definitions and exact international inch, foot, yard, and mile relationships. Some displayed values are rounded for readability, but the calculator keeps more precision internally.