How to Determine Drill Bit Size


Don’t let scattered drill bits ruin your day. Sure, using the wrong one could affect your DIY project, but there’s an easy way to prevent that. If you know how to determine drill bit size, there would be less confusion despite the mess.

There are three resourceful ways of measuring a drill bit. You can just simply check the bit’s shank or use calipers. You can even get creative and make your own 3D chart.

Learn more about the three methods of identifying a drill bit‘s size!

Find the measurement on the shank.

Sometimes, the answer is right under your nose. Just look for the markings on the shank, specifically above the threads. The markings are usually tiny, so look carefully.

If you really couldn’t see the markings, then proceed to plan B.

Use a caliper.

In case you’re unsure about what a caliper looks like, it is similar to a metallic ruler – except for the two jaws on top. The upper jaw is fixed while the bottom one slides up and down to measure a range of sizes.

All you have to do is hold the drill bit between the caliper’s jaws. Slide the bottom jaw until it touches one side of the bit. Then, simply check the measurement.

Create your own drill bit chart.

To avoid measuring your drill bits over and over again, make a chart by drilling holes of different sizes on a piece of metal. Don’t forget to label the holes according to their exact measurements.

The trick is to insert a drill bit on each hole until it fits one. That’s it!


As long as you know how to determine drill bit size, you can’t go wrong with your DIY project no matter the mess. The easiest way is to check for markings on the shank. Meanwhile, creating a chart full of holes can be time-consuming, but it is very helpful for future use.