Other naming systemsABSOLUTE DIAMETER DELTA
fractional-inch drill · nominal diameter
21/32
drill bit size.
A 21/32 bit measures 0.6563 in across (16.669 mm).
The fractional diameter is exact; decimal and metric values are conversions.
Calibrated relative diameter · 1 in reference
21/32 · fractional
0.6563 in
16.669 mm Designation21/32fractional
Inch decimal0.6563nominal
Metric conversion16.669millimetres
Where this size sits from 0 to 1 inch 21/32 · 16.669 mm on a zero to 25.4 millimetre scale. Neighbor marks: 41/64, 43/64.
Measured neighbors
What sits beside 21/32.
“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