#27 Drill Bit Size
A #27 drill bit is 0.1440 inches or 3.66 mm. The closest common fractional drill bit is 9/64 inch at 0.1406 inches.
Quick Answer
Decimal
0.1440 in
Metric
3.66 mm
Closest
9/64 inch
#27 Drill Bit Equivalent Chart
| Size | Decimal Inches | Metric | Note |
|---|---|---|---|
| #27 | 0.1440 in | 3.66 mm | Exact size |
| 9/64 inch | 0.1406 in | 3.57 mm | Closest common fractional undersize |
| 5/32 inch | 0.1563 in | 3.97 mm | Common fractional oversize |
| 3.7 mm | 0.1457 in | 3.70 mm | Nearby metric size |
Common Uses
Tap drilling, clearance holes, and precision work where #27 is specified.
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.
#27 Drill Bit FAQ
What are the inch and metric dimensions for #27?
#27 drill bit measures 0.1440 in and 3.66 mm.
What is the closest common equivalent to #27?
9/64 inch is the closest common equivalent listed here. It measures 0.1406 in or 3.57 mm.
Can I substitute another bit for #27?
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.