#4 Drill Size

number drill

#4 0.209 in 5.31 mm

A #4 drill measures 0.209 in. It taps 2 threads in this chart.

What a #4 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 #4 drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
1/4-20	63.1%	#7	75.4%
M6 x 1	53.2%	5 mm	77.0%

Drills either side

5.3 mm 0.2087 in · 5.3 mm Next size down
5.4 mm 0.2126 in · 5.4 mm Next size up

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

#4 drill: common questions

What size is a #4 drill?

0.209 inches, which is 5.31 mm. It is a number drill.

What can I tap with a #4 drill?

2 threads: 1/4-20 at 63.1%, M6 x 1 at 53.2%.

What drill is next to a #4?

Down: 5.3 mm at 0.2087 in. Up: 5.4 mm at 0.2126 in.