7/8 in Drill Size

fractional drill

7/8″ 0.875 in 22.23 mm

A 7/8 in drill is the standard tap drill for 1-8.

What a 7/8 in drill taps

Every thread this drill cuts between 50% and 85% of thread, deepest first. Outside that band it is the wrong drill for the job, so nothing below that line is listed.

Threads a 7/8 in drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
1-8 chart drill	77.0%	7/8″	77.0%
M24 x 2	68.3%	22 mm	77.0%

Drills either side

22 mm 0.8661 in · 22 mm Next size down
22.5 mm 0.8858 in · 22.5 mm Next size up

All drill sizes → · Open this drill in the calculator →

7/8 in drill: common questions

What size is a 7/8 in drill?

0.875 inches, which is 22.23 mm. It is a fractional drill.

What can I tap with a 7/8 in drill?

2 threads: 1-8 at 77.0%, M24 x 2 at 68.3%.

Is a 7/8 in drill the standard tap drill for anything?

Yes, for 1-8 (77.0% thread). That is the size published tap and drill charts give.

What drill is next to a 7/8 in?

Down: 22 mm at 0.8661 in. Up: 22.5 mm at 0.8858 in.