Guides / Costs and conversions · Updated
Fraction to decimal chart
Inches. Sixteenths, the marks on a tape measure, are in bold. 1 in = 25.4 mm exactly.
Short answer
1/16 in is 0.0625 in, 1/8 is 0.125, 1/4 is 0.25, 3/8 is 0.375, 1/2 is 0.5, 5/8 is 0.625, 3/4 is 0.75 and 7/8 is 0.875. Every 64th is below.
Inch fractions to decimals and millimeters
| Fraction | Decimal | mm |
|---|---|---|
| 1/64 | 0.0156 | 0.397 |
| 1/32 | 0.0313 | 0.794 |
| 3/64 | 0.0469 | 1.191 |
| 1/16 | 0.0625 | 1.588 |
| 5/64 | 0.0781 | 1.984 |
| 3/32 | 0.0938 | 2.381 |
| 7/64 | 0.1094 | 2.778 |
| 1/8 | 0.125 | 3.175 |
| 9/64 | 0.1406 | 3.572 |
| 5/32 | 0.1563 | 3.969 |
| 11/64 | 0.1719 | 4.366 |
| 3/16 | 0.1875 | 4.762 |
| 13/64 | 0.2031 | 5.159 |
| 7/32 | 0.2188 | 5.556 |
| 15/64 | 0.2344 | 5.953 |
| 1/4 | 0.25 | 6.350 |
| 17/64 | 0.2656 | 6.747 |
| 9/32 | 0.2813 | 7.144 |
| 19/64 | 0.2969 | 7.541 |
| 5/16 | 0.3125 | 7.938 |
| 21/64 | 0.3281 | 8.334 |
| 11/32 | 0.3438 | 8.731 |
| 23/64 | 0.3594 | 9.128 |
| 3/8 | 0.375 | 9.525 |
| 25/64 | 0.3906 | 9.922 |
| 13/32 | 0.4063 | 10.319 |
| 27/64 | 0.4219 | 10.716 |
| 7/16 | 0.4375 | 11.112 |
| 29/64 | 0.4531 | 11.509 |
| 15/32 | 0.4688 | 11.906 |
| 31/64 | 0.4844 | 12.303 |
| 1/2 | 0.5 | 12.700 |
| Fraction | Decimal | mm |
|---|---|---|
| 33/64 | 0.5156 | 13.097 |
| 17/32 | 0.5313 | 13.494 |
| 35/64 | 0.5469 | 13.891 |
| 9/16 | 0.5625 | 14.288 |
| 37/64 | 0.5781 | 14.684 |
| 19/32 | 0.5938 | 15.081 |
| 39/64 | 0.6094 | 15.478 |
| 5/8 | 0.625 | 15.875 |
| 41/64 | 0.6406 | 16.272 |
| 21/32 | 0.6563 | 16.669 |
| 43/64 | 0.6719 | 17.066 |
| 11/16 | 0.6875 | 17.463 |
| 45/64 | 0.7031 | 17.859 |
| 23/32 | 0.7188 | 18.256 |
| 47/64 | 0.7344 | 18.653 |
| 3/4 | 0.75 | 19.050 |
| 49/64 | 0.7656 | 19.447 |
| 25/32 | 0.7813 | 19.844 |
| 51/64 | 0.7969 | 20.241 |
| 13/16 | 0.8125 | 20.638 |
| 53/64 | 0.8281 | 21.034 |
| 27/32 | 0.8438 | 21.431 |
| 55/64 | 0.8594 | 21.828 |
| 7/8 | 0.875 | 22.225 |
| 57/64 | 0.8906 | 22.622 |
| 29/32 | 0.9063 | 23.019 |
| 59/64 | 0.9219 | 23.416 |
| 15/16 | 0.9375 | 23.813 |
| 61/64 | 0.9531 | 24.209 |
| 31/32 | 0.9688 | 24.606 |
| 63/64 | 0.9844 | 25.003 |
| 1 | 1 | 25.400 |
Reading a tape measure
The longest marks between inches are halves, then quarters, eighths, and the shortest are sixteenths. Count sixteenths past the last whole inch and reduce: 6/16 is 3/8. So a mark 6 sixteenths past 7 reads 7 3/8 in, or 7.375 in.
To add or subtract lengths in feet and inches without converting by hand, use the feet and inches calculator.
Where the numbers come from
Each decimal is the fraction divided out. Millimeters use 1 in = 25.4 mm, exact by definition (NIST Handbook 44, Appendix C).