1/4 inch Drill Bit Size
A 1/4 inch drill bit is 0.2500 inches or 6.35 mm. It is slightly larger than a 6 mm drill bit.
Quick Answer
Decimal
0.2500 in
Metric
6.35 mm
Closest
6 mm
1/4 inch Drill Bit Equivalent Chart
| Size | Decimal Inches | Metric | Note |
|---|---|---|---|
| 1/4 inch | 0.2500 in | 6.35 mm | Exact size |
| 6 mm | 0.2362 in | 6.00 mm | Common metric undersize |
| F | 0.2570 in | 6.53 mm | Nearby letter drill size |
| 15/64 inch | 0.2344 in | 5.95 mm | Smaller fractional option |
Common Uses
Wall anchors, general drilling, small conduit, and medium hardware.
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.
1/4 inch Drill Bit FAQ
What are the inch and metric dimensions for 1/4 inch?
1/4 inch drill bit measures 0.2500 in and 6.35 mm.
What is the closest common equivalent to 1/4 inch?
6 mm is the closest common equivalent listed here. It measures 0.2362 in or 6.00 mm.
Can I substitute another bit for 1/4 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.