10 mm Drill Bit Size
A 10 mm drill bit is 0.3937 inches. The closest common fractional drill bit is 25/64 inch at 0.3906 inches; 13/32 inch is a common oversize at 0.4063 inches.
Quick Answer
Decimal
0.3937 in
Metric
10.00 mm
Closest
25/64 inch
10 mm Drill Bit Equivalent Chart
| Size | Decimal Inches | Metric | Note |
|---|---|---|---|
| 10 mm | 0.3937 in | 10.00 mm | Exact size |
| 25/64 inch | 0.3906 in | 9.92 mm | Closest common fractional size |
| 13/32 inch | 0.4063 in | 10.32 mm | Common fractional oversize |
| 3/8 inch | 0.3750 in | 9.53 mm | Common undersize, not an exact substitute |
Common Uses
Larger anchors, conduit holes, metric fastener clearance, and general fabrication.
Exact vs Nearest Size
Choose the exact bit for threads, tight hardware fits, dowels, and precision layouts. Use the nearest common equivalent only for rough pilot holes, clearance holes, or material removal where a slight difference is acceptable.
10 mm Drill Bit FAQ
What are the inch and metric dimensions for 10 mm?
10 mm drill bit measures 0.3937 in and 10.00 mm.
What is the closest common equivalent to 10 mm?
25/64 inch is the closest common equivalent listed here. It measures 0.3906 in or 9.92 mm.
Can I substitute another bit for 10 mm?
Use the exact bit size for tap drilling, precision holes, dowels, and manufacturer-specified hardware. A nearby fractional, metric, numbered, or letter drill bit is usually fine only for clearance holes or rough pilot holes.