Other naming systemsABSOLUTE DIAMETER DELTA
fractional-inch drill · nominal diameter
63/64
drill bit size.
A 63/64 bit measures 0.9844 in across (25.003 mm).
The fractional diameter is exact; decimal and metric values are conversions.
Calibrated relative diameter · 1 in reference
63/64 · fractional
0.9844 in
25.003 mm Designation63/64fractional
Inch decimal0.9844nominal
Metric conversion25.003millimetres
Where this size sits from 0 to 1 inch 63/64 · 25.003 mm on a zero to 25.4 millimetre scale. Neighbor marks: 31/32, 1.
Measured neighbors
What sits beside 63/64.
“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.
Source record
Drill Bit Size Chart.
Fractional sizes are exact rational multiples of one inch.
Open source record