Fractional Inch to MM Chart
1/16β³ through 1β³ Β· exact values
Definition
1 inch = 25.4 mm
Exact by international agreement (1959)
Fractional inch conversion table
| Fraction | Sixteenths | mm | cm |
|---|---|---|---|
| 1/16β³ | 1/16 | 1.5875 | 0.1588 |
| 1/8β³ | 2/16 | 3.175 | 0.3175 |
| 3/16β³ | 3/16 | 4.7625 | 0.4762 |
| 1/4β³ | 4/16 | 6.35 | 0.635 |
| 5/16β³ | 5/16 | 7.9375 | 0.7937 |
| 3/8β³ | 6/16 | 9.525 | 0.9525 |
| 7/16β³ | 7/16 | 11.1125 | 1.1112 |
| 1/2β³ | 8/16 | 12.7 | 1.27 |
| 9/16β³ | 9/16 | 14.2875 | 1.4287 |
| 5/8β³ | 10/16 | 15.875 | 1.5875 |
| 11/16β³ | 11/16 | 17.4625 | 1.7462 |
| 3/4β³ | 12/16 | 19.05 | 1.905 |
| 13/16β³ | 13/16 | 20.6375 | 2.0637 |
| 7/8β³ | 14/16 | 22.225 | 2.2225 |
| 15/16β³ | 15/16 | 23.8125 | 2.3813 |
| 1β³ | 16/16 | 25.4 | 2.54 |
32ths of an inch
| Fraction | In 32ths | mm | Decimal in |
|---|---|---|---|
| 1/32β³ | 1/32 | 0.79375 | 0.03125 |
| 3/32β³ | 3/32 | 2.38125 | 0.09375 |
| 5/32β³ | 5/32 | 3.96875 | 0.15625 |
| 7/32β³ | 7/32 | 5.55625 | 0.21875 |
| 9/32β³ | 9/32 | 7.14375 | 0.28125 |
| 11/32β³ | 11/32 | 8.73125 | 0.34375 |
| 13/32β³ | 13/32 | 10.31875 | 0.40625 |
| 15/32β³ | 15/32 | 11.90625 | 0.46875 |
| 17/32β³ | 17/32 | 13.49375 | 0.53125 |
| 19/32β³ | 19/32 | 15.08125 | 0.59375 |
| 21/32β³ | 21/32 | 16.66875 | 0.65625 |
| 23/32β³ | 23/32 | 18.25625 | 0.71875 |
| 25/32β³ | 25/32 | 19.84375 | 0.78125 |
| 27/32β³ | 27/32 | 21.43125 | 0.84375 |
| 29/32β³ | 29/32 | 23.01875 | 0.90625 |
| 31/32β³ | 31/32 | 24.60625 | 0.96875 |
64ths of an inch
| Fraction | In 64ths | mm | Decimal in |
|---|---|---|---|
| 1/64β³ | 1/64 | 0.396875 | 0.015625 |
| 3/64β³ | 3/64 | 1.190625 | 0.046875 |
| 5/64β³ | 5/64 | 1.984375 | 0.078125 |
| 7/64β³ | 7/64 | 2.778125 | 0.109375 |
| 9/64β³ | 9/64 | 3.571875 | 0.140625 |
| 11/64β³ | 11/64 | 4.365625 | 0.171875 |
| 13/64β³ | 13/64 | 5.159375 | 0.203125 |
| 15/64β³ | 15/64 | 5.953125 | 0.234375 |
| 17/64β³ | 17/64 | 6.746875 | 0.265625 |
| 19/64β³ | 19/64 | 7.540625 | 0.296875 |
| 21/64β³ | 21/64 | 8.334375 | 0.328125 |
| 23/64β³ | 23/64 | 9.128125 | 0.359375 |
| 25/64β³ | 25/64 | 9.921875 | 0.390625 |
| 27/64β³ | 27/64 | 10.715625 | 0.421875 |
| 29/64β³ | 29/64 | 11.509375 | 0.453125 |
| 31/64β³ | 31/64 | 12.303125 | 0.484375 |
| 33/64β³ | 33/64 | 13.096875 | 0.515625 |
| 35/64β³ | 35/64 | 13.890625 | 0.546875 |
| 37/64β³ | 37/64 | 14.684375 | 0.578125 |
| 39/64β³ | 39/64 | 15.478125 | 0.609375 |
| 41/64β³ | 41/64 | 16.271875 | 0.640625 |
| 43/64β³ | 43/64 | 17.065625 | 0.671875 |
| 45/64β³ | 45/64 | 17.859375 | 0.703125 |
| 47/64β³ | 47/64 | 18.653125 | 0.734375 |
| 49/64β³ | 49/64 | 19.446875 | 0.765625 |
| 51/64β³ | 51/64 | 20.240625 | 0.796875 |
| 53/64β³ | 53/64 | 21.034375 | 0.828125 |
| 55/64β³ | 55/64 | 21.828125 | 0.859375 |
| 57/64β³ | 57/64 | 22.621875 | 0.890625 |
| 59/64β³ | 59/64 | 23.415625 | 0.921875 |
| 61/64β³ | 61/64 | 24.209375 | 0.953125 |
| 63/64β³ | 63/64 | 25.003125 | 0.984375 |
FAQ
Why are fractional inch conversions exact?
The 1959 international yard and pound agreement defined the inch as exactly 25.4 mm. Because 25.4 divides cleanly by powers of two, values like 1/16β³ (1.5875 mm) terminate rather than repeat.
How do I convert any fraction to mm?
Multiply 25.4 by the numerator, then divide by the denominator. For 5/8β³: 25.4 Γ 5 Γ· 8 = 15.875 mm.
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