mm ↔ inch ↔ fractions
Inch / Metric Conversion
Convert between millimeters, decimal inches and fractional inches to 1/64 resolution, with the complete fraction–decimal–metric chart used on every shop wall.
mm ↔ inch ↔ fraction
1 in = 25.4 mm exactlyFraction – decimal – millimeter chart (1/64″)
| Fraction (in) | Decimal (in) | Millimeters (mm) |
|---|---|---|
| 0 | 0. | 0 |
| 1/64 | 0.015625 | 0.3969 |
| 1/32 | 0.03125 | 0.7937 |
| 3/64 | 0.046875 | 1.1906 |
| 1/16 | 0.0625 | 1.5875 |
| 5/64 | 0.078125 | 1.9844 |
| 3/32 | 0.09375 | 2.3812 |
| 7/64 | 0.109375 | 2.7781 |
| 1/8 | 0.125 | 3.175 |
| 9/64 | 0.140625 | 3.5719 |
| 5/32 | 0.15625 | 3.9688 |
| 11/64 | 0.171875 | 4.3656 |
| 3/16 | 0.1875 | 4.7625 |
| 13/64 | 0.203125 | 5.1594 |
| 7/32 | 0.21875 | 5.5562 |
| 15/64 | 0.234375 | 5.9531 |
| 1/4 | 0.25 | 6.35 |
| 17/64 | 0.265625 | 6.7469 |
| 9/32 | 0.28125 | 7.1437 |
| 19/64 | 0.296875 | 7.5406 |
| 5/16 | 0.3125 | 7.9375 |
| 21/64 | 0.328125 | 8.3344 |
| 11/32 | 0.34375 | 8.7312 |
| 23/64 | 0.359375 | 9.1281 |
| 3/8 | 0.375 | 9.525 |
| 25/64 | 0.390625 | 9.9219 |
| 13/32 | 0.40625 | 10.3187 |
| 27/64 | 0.421875 | 10.7156 |
| 7/16 | 0.4375 | 11.1125 |
| 29/64 | 0.453125 | 11.5094 |
| 15/32 | 0.46875 | 11.9062 |
| 31/64 | 0.484375 | 12.3031 |
| 1/2 | 0.5 | 12.7 |
| 33/64 | 0.515625 | 13.0969 |
| 17/32 | 0.53125 | 13.4937 |
| 35/64 | 0.546875 | 13.8906 |
| 9/16 | 0.5625 | 14.2875 |
| 37/64 | 0.578125 | 14.6844 |
| 19/32 | 0.59375 | 15.0812 |
| 39/64 | 0.609375 | 15.4781 |
| 5/8 | 0.625 | 15.875 |
| 41/64 | 0.640625 | 16.2719 |
| 21/32 | 0.65625 | 16.6687 |
| 43/64 | 0.671875 | 17.0656 |
| 11/16 | 0.6875 | 17.4625 |
| 45/64 | 0.703125 | 17.8594 |
| 23/32 | 0.71875 | 18.2562 |
| 47/64 | 0.734375 | 18.6531 |
| 3/4 | 0.75 | 19.05 |
| 49/64 | 0.765625 | 19.4469 |
| 25/32 | 0.78125 | 19.8438 |
| 51/64 | 0.796875 | 20.2406 |
| 13/16 | 0.8125 | 20.6375 |
| 53/64 | 0.828125 | 21.0344 |
| 27/32 | 0.84375 | 21.4312 |
| 55/64 | 0.859375 | 21.8281 |
| 7/8 | 0.875 | 22.225 |
| 57/64 | 0.890625 | 22.6219 |
| 29/32 | 0.90625 | 23.0187 |
| 59/64 | 0.921875 | 23.4156 |
| 15/16 | 0.9375 | 23.8125 |
| 61/64 | 0.953125 | 24.2094 |
| 31/32 | 0.96875 | 24.6062 |
| 63/64 | 0.984375 | 25.0031 |
| 1 | 1.0 | 25.4 |
Formulas used
Definition: 1 inch = 25.4 mm exactly (international yard and pound agreement, 1959)
Frequently asked questions
How many mm is 1/2 inch?
12.7 mm exactly. Every fractional inch converts through the exact 25.4 mm/inch definition.
What is 10 mm in inches as a fraction?
10 mm = 0.3937 in, which is 25/64 in to the nearest 1/64 (0.3906 in) — about 0.003 in under.