Length
mm to fractional inches Converter
Convert millimeters to decimal inches and the nearest common inch fraction.
Convert mm to inch fractions
Fractional inch sizes are rounded to the nearest selected fraction and reduced, such as 32/64 becoming 1/2.
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.
mm to fractional inches chart
| Millimeters | Decimal inches | Nearest 1/64 | Nearest 1/32 |
|---|---|---|---|
| 1 mm | 0.03937 in | 3/64 in | 1/32 in |
| 2 mm | 0.07874 in | 5/64 in | 3/32 in |
| 3 mm | 0.11811 in | 1/8 in | 1/8 in |
| 4 mm | 0.15748 in | 5/32 in | 5/32 in |
| 5 mm | 0.19685 in | 13/64 in | 3/16 in |
| 6 mm | 0.23622 in | 15/64 in | 1/4 in |
| 8 mm | 0.31496 in | 5/16 in | 5/16 in |
| 10 mm | 0.3937 in | 25/64 in | 13/32 in |
| 12 mm | 0.47244 in | 15/32 in | 15/32 in |
| 16 mm | 0.62992 in | 5/8 in | 5/8 in |
| 20 mm | 0.7874 in | 25/32 in | 25/32 in |
| 25 mm | 0.98425 in | 63/64 in | 31/32 in |
| 30 mm | 1.1811 in | 1 3/16 in | 1 3/16 in |
| 50 mm | 1.9685 in | 1 31/32 in | 1 31/32 in |
Formula
inches = mm / 25.4; nearest fraction = round(inches x denominator) / denominator
Source
SI meter definitions and exact international inch, foot, yard, and mile relationships.
Common questions
How does the mm to fractional inches Converter work?
Convert millimeters to decimal inches and the nearest common inch fraction.
What formula does this calculator use?
inches = mm / 25.4; nearest fraction = round(inches x denominator) / denominator
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.