1/2 inch Drill Bit Size
A 1/2 inch drill bit is 0.5000 inches or 12.70 mm. It is larger than a 12 mm drill bit.
Quick Answer
Decimal
0.5000 in
Metric
12.70 mm
Closest
13 mm
1/2 inch Drill Bit Equivalent Chart
| Size | Decimal Inches | Metric | Note |
|---|---|---|---|
| 1/2 inch | 0.5000 in | 12.70 mm | Exact size |
| 13 mm | 0.5118 in | 13.00 mm | Common metric oversize |
| 12 mm | 0.4724 in | 12.00 mm | Common metric undersize |
| 31/64 inch | 0.4844 in | 12.30 mm | Smaller fractional option |
Common Uses
Large holes, conduit, plumbing, and heavy hardware clearance.
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.
1/2 inch Drill Bit FAQ
What are the inch and metric dimensions for 1/2 inch?
1/2 inch drill bit measures 0.5000 in and 12.70 mm.
What is the closest common equivalent to 1/2 inch?
13 mm is the closest common equivalent listed here. It measures 0.5118 in or 13.00 mm.
Can I substitute another bit for 1/2 inch?
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.