Convert any decimal to its exact common fraction (or nearest 64th for imperial measurements) — with a reference chart.
| Input | Result |
|---|---|
| 0.375 | 3/8 (exact) |
| 0.5 | 1/2 (exact) |
| 0.125 | 1/8 (exact) |
| 0.333 | ≈ 21/64 (nearest 64th — no exact small fraction) |
| Decimal | Fraction | Decimal | Fraction |
|---|---|---|---|
| 0.0625 | 1/16 | 0.5 | 1/2 |
| 0.125 | 1/8 | 0.5625 | 9/16 |
| 0.1875 | 3/16 | 0.625 | 5/8 |
| 0.25 | 1/4 | 0.6875 | 11/16 |
| 0.3125 | 5/16 | 0.75 | 3/4 |
| 0.375 | 3/8 | 0.8125 | 13/16 |
| 0.4375 | 7/16 | 0.875 | 7/8 |
| 0.4375 (0.43750) | 7/16 | 0.9375 | 15/16 |
Why 64ths? Imperial rulers, drill bits and machining tolerances work in 1/64-inch steps. Any decimal that doesn't terminate in a 64th is an approximation — choose the closest and note the tolerance.
Count the decimal places, put the digits over that power of ten, and reduce: 0.375 = 375/1000 = 3/8 (divide top and bottom by 125). The calculator does the same search and stops at the smallest denominator.
0.333 (with the 3 repeating forever) equals exactly 1/3 — but 1/3 has denominator 3, which no 64th-based ruler can show. The tool's fallback gives the nearest 1/64: 21/64 = 0.328125.
Woodworking and machining: tapes and calipers read in 64ths, so the nearest 64th is the practical fraction you can actually measure and cut.