15/16" drill bit size
0.9375 in
23.81 mm · fractional drill
| Inches | 0.9375 in |
| Millimetres | 23.81 mm |
| Nearest metric drill | 23.8 mm |
| System | Fractional (64ths) |
What 15/16" means
15/16" is a fractional drill, stepping in 64ths of an inch. Fractional sizes are the coarsest of the three systems, which is why a fractional set alone cannot hit most tapping sizes and why number and letter drills exist at all.
The same hole in the other systems
Three drill systems overlap across this range and a workshop rarely has all three. The nearest bit of each other kind to 15/16":
| System | Nearest size | Difference |
|---|---|---|
| number | #1 — 0.228 in | 0.7095 in smaller |
| letter | Z — 0.413 in | 0.5245 in smaller |
| metric | 23.8 mm | 0.012 mm smaller |
The closest substitute is 0.5245 inches away. For a clearance hole that is nothing; for a tapping hole it moves the thread engagement by several per cent, which is the difference between an easy tap and a broken one.
What gets drilled at 0.9375 inches
Half an inch and up is where twist drills stop being the obvious tool. A bit this size in mild steel needs a pilot, a slow speed and something to hold the work; past three-quarters of an inch most people reach for a hole saw or a step drill instead.
Either side of it
| Drill | Inches | Millimetres |
|---|---|---|
| 57/64" | 0.8906 in | 22.62 mm |
| 29/32" | 0.9063 in | 23.02 mm |
| 59/64" | 0.9219 in | 23.42 mm |
| 15/16" | 0.9375 in | 23.81 mm |
| 61/64" | 0.9531 in | 24.21 mm |
| 31/32" | 0.9688 in | 24.61 mm |
| 63/64" | 0.9844 in | 25 mm |
Frequently asked questions
What size is a 15/16" drill bit?
0.9375 inches, which is 23.81 mm. Fractional drills step in 64ths of an inch, which is the coarsest of the three systems and the one most home sets contain.
What is a 15/16" drill bit in mm?
23.81 mm. A metric index will offer 23.8 mm as the nearest stocked size, which is near enough identical.
Is 15/16" a tapping drill size?
Not for any of the unified threads on this site. It sits between the sizes the standard taps call for, so it is a clearance or pilot drill rather than a tapping one.
What is the next size up from 15/16"?
61/64" at 0.9531 inches — 0.0156 inches larger. Below it is 59/64" at 0.9219.
Other sizes
- 61/64" drill bit — 0.9531 in, 24.21 mm
- 31/32" drill bit — 0.9688 in, 24.61 mm
- 63/64" drill bit — 0.9844 in, 25 mm
- 1/1" drill bit — 1 in, 25.4 mm
- 1/64" drill bit — 0.0156 in, 0.4 mm
- 1/32" drill bit — 0.0313 in, 0.79 mm
- #60 drill bit — 0.04 in, 1.02 mm
- #59 drill bit — 0.041 in, 1.04 mm