Sixteenths chart (tape measure)
| Fraction | Decimal | mm |
|---|---|---|
| 1/16" | 0.0625 | 1.59 |
| 1/8" | 0.125 | 3.18 |
| 3/16" | 0.1875 | 4.76 |
| 1/4" | 0.25 | 6.35 |
| 5/16" | 0.3125 | 7.94 |
| 3/8" | 0.375 | 9.53 |
| 7/16" | 0.4375 | 11.11 |
| 1/2" | 0.5 | 12.70 |
| 9/16" | 0.5625 | 14.29 |
| 5/8" | 0.625 | 15.88 |
| 11/16" | 0.6875 | 17.46 |
| 3/4" | 0.75 | 19.05 |
| 13/16" | 0.8125 | 20.64 |
| 7/8" | 0.875 | 22.23 |
| 15/16" | 0.9375 | 23.81 |
| 1" | 1 | 25.40 |
Fraction to decimal chart in 64ths, with mm
Every 1/64" step has a finite decimal, so the decimals below are exact. Millimeters are rounded to 0.001 mm.
| Fraction | 64ths | Decimal | mm |
|---|---|---|---|
| 1/64" | 1/64 | 0.015625 | 0.397 |
| 1/32" | 2/64 | 0.031250 | 0.794 |
| 3/64" | 3/64 | 0.046875 | 1.191 |
| 1/16" | 4/64 | 0.062500 | 1.588 |
| 5/64" | 5/64 | 0.078125 | 1.984 |
| 3/32" | 6/64 | 0.093750 | 2.381 |
| 7/64" | 7/64 | 0.109375 | 2.778 |
| 1/8" | 8/64 | 0.125000 | 3.175 |
| 9/64" | 9/64 | 0.140625 | 3.572 |
| 5/32" | 10/64 | 0.156250 | 3.969 |
| 11/64" | 11/64 | 0.171875 | 4.366 |
| 3/16" | 12/64 | 0.187500 | 4.763 |
| 13/64" | 13/64 | 0.203125 | 5.159 |
| 7/32" | 14/64 | 0.218750 | 5.556 |
| 15/64" | 15/64 | 0.234375 | 5.953 |
| 1/4" | 16/64 | 0.250000 | 6.350 |
| 17/64" | 17/64 | 0.265625 | 6.747 |
| 9/32" | 18/64 | 0.281250 | 7.144 |
| 19/64" | 19/64 | 0.296875 | 7.541 |
| 5/16" | 20/64 | 0.312500 | 7.938 |
| 21/64" | 21/64 | 0.328125 | 8.334 |
| 11/32" | 22/64 | 0.343750 | 8.731 |
| 23/64" | 23/64 | 0.359375 | 9.128 |
| 3/8" | 24/64 | 0.375000 | 9.525 |
| 25/64" | 25/64 | 0.390625 | 9.922 |
| 13/32" | 26/64 | 0.406250 | 10.319 |
| 27/64" | 27/64 | 0.421875 | 10.716 |
| 7/16" | 28/64 | 0.437500 | 11.113 |
| 29/64" | 29/64 | 0.453125 | 11.509 |
| 15/32" | 30/64 | 0.468750 | 11.906 |
| 31/64" | 31/64 | 0.484375 | 12.303 |
| 1/2" | 32/64 | 0.500000 | 12.700 |
| 33/64" | 33/64 | 0.515625 | 13.097 |
| 17/32" | 34/64 | 0.531250 | 13.494 |
| 35/64" | 35/64 | 0.546875 | 13.891 |
| 9/16" | 36/64 | 0.562500 | 14.288 |
| 37/64" | 37/64 | 0.578125 | 14.684 |
| 19/32" | 38/64 | 0.593750 | 15.081 |
| 39/64" | 39/64 | 0.609375 | 15.478 |
| 5/8" | 40/64 | 0.625000 | 15.875 |
| 41/64" | 41/64 | 0.640625 | 16.272 |
| 21/32" | 42/64 | 0.656250 | 16.669 |
| 43/64" | 43/64 | 0.671875 | 17.066 |
| 11/16" | 44/64 | 0.687500 | 17.463 |
| 45/64" | 45/64 | 0.703125 | 17.859 |
| 23/32" | 46/64 | 0.718750 | 18.256 |
| 47/64" | 47/64 | 0.734375 | 18.653 |
| 3/4" | 48/64 | 0.750000 | 19.050 |
| 49/64" | 49/64 | 0.765625 | 19.447 |
| 25/32" | 50/64 | 0.781250 | 19.844 |
| 51/64" | 51/64 | 0.796875 | 20.241 |
| 13/16" | 52/64 | 0.812500 | 20.638 |
| 53/64" | 53/64 | 0.828125 | 21.034 |
| 27/32" | 54/64 | 0.843750 | 21.431 |
| 55/64" | 55/64 | 0.859375 | 21.828 |
| 7/8" | 56/64 | 0.875000 | 22.225 |
| 57/64" | 57/64 | 0.890625 | 22.622 |
| 29/32" | 58/64 | 0.906250 | 23.019 |
| 59/64" | 59/64 | 0.921875 | 23.416 |
| 15/16" | 60/64 | 0.937500 | 23.813 |
| 61/64" | 61/64 | 0.953125 | 24.209 |
| 31/32" | 62/64 | 0.968750 | 24.606 |
| 63/64" | 63/64 | 0.984375 | 25.003 |
| 1" | 64/64 | 1.000000 | 25.400 |
How the rounding works
- Multiply the decimal part by the denominator — 16 for sixteenths — and round to the nearest whole number. Halfway values round up.
- Reduce the fraction: 6/16 becomes 3/8. If it rounds all the way up (16/16), the whole number goes up by one.
- The error is the fraction minus your measurement: + means the fraction is a little longer, − a little shorter.
- Millimeters use the exact definition 1 in = 25.4 mm. For other units, use the unit converter.
Frequently asked questions
How do I convert a decimal to a fraction in inches?
Multiply the decimal part by the denominator you want (16 for sixteenths), round to the nearest whole number, then reduce. 0.375 × 16 = 6, and 6/16 reduces to 3/8 — so 0.375" is 3/8".
What is 0.3 inch as a fraction?
About 5/16" (0.3125"), which is 0.0125" over. To the nearest 1/64 it is 19/64" (0.296875"), 0.0031" under.
How many millimeters is an inch?
Exactly 25.4 mm. The international inch has been defined that way since 1959, so the conversion is exact, not rounded.
Which precision should I use?
Most tape measures mark sixteenths, so 1/16" suits woodworking and carpentry. Use 1/32" or 1/64" for machining and close fits, and 1/8" when a rough mark is enough.
What happens when a value is exactly halfway between two fractions?
This converter rounds halfway values up, and always shows the error so you can see which way it went. 0.15625" at 1/16" becomes 3/16", 0.03125" over.