10.3 mm Drill Size

metric drill

10.3 mm 0.4055 in 10.30 mm

A 10.3 mm drill measures 0.4055 in. It taps 2 threads in this chart.

What a 10.3 mm 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 10.3 mm drill taps, with the percent of thread each one gets and the published chart drill for comparison.
Thread	% thread	Chart drill	Chart %
M12 x 1.75	74.8%	10.2 mm	79.2%
7/16-28	69.0%	Y	72.2%

Drills either side

Y 0.404 in · 10.26 mm Next size down
13/32″ 0.4062 in · 10.32 mm Next size up

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

10.3 mm drill: common questions

What size is a 10.3 mm drill?

0.4055 inches, which is 10.30 mm. It is a metric drill.

What can I tap with a 10.3 mm drill?

2 threads: M12 x 1.75 at 74.8%, 7/16-28 at 69.0%.

What drill is next to a 10.3 mm?

Down: Y at 0.404 in. Up: 13/32 in at 0.4062 in.