P Drill Size

letter drill

P 0.323 in 8.20 mm

A P drill measures 0.323 in. It taps 1 thread in this chart.

What a P 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 P drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
3/8-16	64.0%	5/16″	77.0%

Drills either side

O 0.316 in · 8.03 mm Next size down
8.4 mm 0.3307 in · 8.4 mm Next size up

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

P drill: common questions

What size is a P drill?

0.323 inches, which is 8.20 mm. It is a letter drill.

What can I tap with a P drill?

1 thread: 3/8-16 at 64.0%.

What drill is next to a P?

Down: O at 0.316 in. Up: 8.4 mm at 0.3307 in.