Drill Bit Size Chart – 2021 Guide

| Last Updated: March 20, 2021

Whether you are looking for a major room upgrade or thinking of a quick decor change, a drill is a tool that will come in quite handy. 

However, without the right drill bit size, a drill will be useless. 

Here we will talk about which drill bit size is suitable for a particular purpose and how can choosing the right size affect your project. 

What is a Drill Bit?

A drill bit is a cutting tool used with the drill to create holes in almost any material. Drill bits come in various sizes and shapes. They are attached to the drill, which, when switched on, rotates to power through the workpiece, creating holes of circular cross-section. To use them, insert the upper end, also known as the shank, into the chuck in the drill. The drill bit will then spin clockwise to create a hole.

Why Does the Size of My Drill Bit Matter?

Different drill bit sizes are suitable for different purposes. The first and foremost thing is to ensure that the size of the drill bits shank matches your drill size. Drills with a ⅜-inch chuck will accept bits that are ⅜-inches in diameter. Also, drills with half an inch chuck will work with larger bits that are half-inch in diameter. 

Choosing the right size of the drill bit will mean that you will be able to get the hole drilled with the least amount of trouble and without causing any damage to the material, yourself, or the tools. 

You can drill just about anything - it all depends on picking the right bit size. You can drill soft materials with any bit, but for hard or brittle materials like acrylic or glass, you might need specially designed bits. There are also bits for drilling holes into concrete, plastic, metal, wood, and other materials. 

What Happens if My Drill Bit’s Too Big?

If your drill bit is too big, it will slip when you are driving the screw or inserting the bit. Moreover, it will prevent the screw from gripping the wood.

What Will Happen if My Drill Bit is Too Small?

If your drill bit is too small, there is a chance that the wood would crack when you insert the screw.  

What Size Drill Bit Do I Need? 

Pilot hole charts are available with drill bits that make it easy to choose the right one for the job. These charts act as guidelines and are based on the screw shank. 

When you are drilling into softwoods, always choose a bit 1/64-inch smaller than the target hole size. However, when you are drilling into other materials, choose a bit that is exactly the same size as the hole. In case you are not sure which one to choose, use a drill bit that is 1/64-inch larger than the hole you want to drill. 

Choosing the right drill bit can be quite intimidating; however, with practice and experience, you can become proficient easily. Make sure that you refer to the pilot hole charts before making a selection. Also, keep your bits properly organized in a storage case as it will make choosing the right size simpler and more intuitive.

Drill Bit Size Chart


A drill is a multi-purpose and highly indispensable tool which comes in quite handy when you are undertaking improvement projects around your home. Its versatility can be increased with various-sized attachable bits that are uniquely suited to a particular job or material. Make sure that you familiarize yourself with the drill bit size chart so that you can choose the right bit for the job.

People Also Ask

Bits can be intimidating, and there is a chance that people may become confused when selecting the right size bit, especially if they are new to home DIY projects. We have answered some of the commonly asked questions below to make the selection process easier for everyone.

What Drill Bit to Use for Screw Size?

The size of the drill bit should be the same as the screw shaft without taking the threads into account. You can do this simply by measuring the screw side by side with the drill bit. If both the drill bit and the screw are the same sizes, then you are good to go. 

Moreover, you can refer to the measurements that are typically found on most screws and bits. In case you do not find an exact match, use the drill bit that is slightly smaller than the body of the screw.  

How to Determine a Drill Bit Size

Typically, drill bits are marked with their size above the threads on the shank. These markings are stamped into the metal and may read ¼-inch, 3/6-inch, or 25/32-inch.