metric comparison size · nominal diameter
10.3 mm
drill bit size.
A 10.3 mm bit measures 0.4055 in across (10.300 mm).
The metric diameter is the generated reference value; inches are a conversion. Commercial set contents vary.
Calibrated relative diameter · 1 in reference
10.3 mm · metric
0.4055 in
10.300 mm Designation10.3 mmmetric
Inch decimal0.4055nominal
Metric conversion10.300millimetres
Where this size sits from 0 to 1 inch 10.3 mm · 10.300 mm on a zero to 25.4 millimetre scale. Neighbor marks: 13/32, Y.
Measured neighbors
What sits beside 10.3 mm.
“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.
A generated comparison series from 0.5 to 13.0 mm in 0.1 mm steps. It is not a claim that every size is included in every commercial set.
Open source record