# Drill Bit Size Chart and Different Types in metric, gauge size and more…

A drill is one of the larger tools to make holes during construction. The piece of material that creates the holes is called the drill bit. Drill bits come in a wide range of sizes and different measurement systems. The information could even seem overwhelming if you do your research for the first time (skip straight to the Drill Bit Size Chart).

Fortunately, this article is a complete guide on the different ways of sizing drill bits. You’ll find the metric units, letter sizes, fractional inch, and American drill gauge sizes in this piece.

Jump right into the Frequently Asked Questions

## How to Choose the Right Drill Bit Size

The choice of a drill bit is mainly connected to the screw size you want to use afterward. Drill bits are measured using different systems, including metric sizes, fractional sizes, number gauge sizes, and letter systems. Each takes a unique approach, and you’ll need to know the difference to ensure you select the right drill bit size. In this section, we’ll talk about how drill bits are sized.

• Metric drill bit size chart

Metric drill bit sizes are mostly used in Europe and represent the diameter in millimeters. Luckily, our metric drill size chart provided the equivalent of the diameter in inches.

• Number and letter gauge drill sizes

These sizing systems date back to the 19th Century but are still in use. Metric systems are slowly replacing them in some regions like Europe. The gauge numbers are organized in reverse sequence, with #1 as the largest and #107 as the smallest.

On the other hand, the letter sizes appear in ascending order, with A as the smallest and Z as the largest.

• Fractional Inch drill bit size chart

Fractional wire sizes represent the diameters in fractions. This system originated from the American Society of Mechanical Engineers (ASME) and is meant for twist drills. The highest value in fractional drill bits is 1 inch, and the smallest is 1/64 of an inch.

## The Best Type of Drill Bit for You

There’s more to drill bits than just the sizes. You also need to know the different types of drill bits, especially when undertaking high-precision applications. Drill bits are made from various materials and have different surface finishes. These two factors determine the type of surfaces the drill can penetrate.

Let’s discuss the most common drill bits below.

### 1. Twist Drill Bits

This is the most common drill bit you’ll find in hardware and online stores. They can easily drill through metal, wood, and plastic and are designed to throw the material out when drilling. Twist drill bits are either High-Speed Steel (HSS) or carbon steel.

Carbon steel bits aren’t strong enough to drill metal, so they are better for soft materials like wood. HSS is extremely durable and can make holes through harder surfaces.

### 2. Wood Drill Bits

Wood drill bits will do if you use plasterboards and timber in a construction project. They are also designed to drill softer material rather than concrete or metal. Check out the different forms of wood drill bits in this post.

### 3. Masonry Drill Bits

These are ideal for the hardest surfaces, including concrete, bricks, tiles, and other stones. When using these, you should maintain a slow but steady pace to prevent overheating. Additionally, You’ll have to remove the drill periodically to remove the accumulating materials in the hole.

### 4. Tile Drill Bits

These drill bits are perfect for tile installation and can create holes in porcelain, glass, and ceramic tiles without causing cracks.

Drill bit sizing explained (video)

## Frequently Asked Questions on Drill Bit Size Chart

### 1. What are standard drill bit sizes?

The common drill bit sizes appear in different systems, including metric, fractional, letter, and number gauges. We’ve covered the standard sizes in earlier sections of this post.

### 2. What size is a 1/8 drill bit?

A 1/8 drill bit has a diameter of 0.125 inches which equals 3.175 mm.

### 3. How are drills sized?

Drill bits are sized according to the thickness of their diameter. While there are different sizing systems, all of them use the value of the diameter.

### 4. How do you read a drill size?

The letter or number on your drill bit doesn’t directly correspond to the actual size. Once you know the size labeled on your bit, you should compare it with our size charts to find the real size.

### 5. Is a 1/4 drill bit 6mm?

Yes, it is. A quarter-inch drill bit has a diameter of 6.4 mm.

## Conclusion

Drill bits come in a wide variety of sizes. Choosing the right size can help make your construction project easier and faster. Other considerations include the drill bit types and the surface you’re working on. The measurements in our guides are in metric, letter, gauge, and fractional systems. So you can find a familiar chart for your needs.

Feel free to ask any questions about drill bit sizes in the section below.

Picture in this post is by Russ Ward on Unsplash