Find Different Standard Drill Bit Sizes In MM

The standard drill bit is the most common tool used for DIY and professional projects. It comes in inches and mm sizes. For smooth drilling projects, you must know the correct size of the drill bit. You may have a drill bit set in inches, but what is its equivalent standard drill bit in mm?

A standard drill bit in mm is a micro, fractional, metric, spade, masonry, and Forstner drill bit. They come in different sizes in mm, which makes them compatible with different purposes.

However, I will explore the standard drill bit sizes in mm and their equivalents.

What Is a Standard Drill Bit?

A standard drill bit is used to drill cylindrical holes in wood, metal, plastic, and many other materials.

This type of tool is made of high-quality materials such as tungsten carbide or high-strength steel. You will get several options with different shapes and sizes to choose from.

Usually, the standard drill bit has a pointed tip and a cylindrical shank. When it comes to drilling angles or square holes, you can depend on it.

Let’s See the Standard Drill Bit Sizes in mm

Okay, now have a look at some of the major drill bits’ size conversion in millimeters.

Standard Drill BitSize in InchSize in mm
Micro or miniature0.00196 – 0.059 0.05 – 1.5
Fractional drill bit0.015 – 0.50.39  – 12.7
Metric drill bit0.0196 – 0.5110.5 – 13
Spade drill bit1 – 625.4 – 152.4
Masonry drill bit0.11 – 0.623 -16
Forstner drill bit0.25 – 26.35 – 50.8

How Do You Know What Size a Drill Bit Is?

You have many ways to know what size drill bit you have. Below are some major ways to know the size of the drill bit that Engineering Click shows.

  • Many drill bits come with measurements (written) on the tip or shank. You can read the markings to know the drill bit size in mm or inches.
  • If you don’t have the markings, use a drill bit gauge. You can easily measure the size of a drill bit by comparing it to the set of drilled holes in the gauge tool.
  • You can also use a vernier or digital caliper to measure the drill bit size in mm or inches.
  • Some of the drill bit sets come with a size chart. You can also confirm your drill bit size from the available chart. If you need a chart with a drill bit set, then check for the online drill bit size charts.-
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What Are the Different Sizes of Drill Bits?

Different Sizes of Drill Bits

Many drill bit sizes are used for DIY or professional projects. Here I will share the few major drill bit sizes common in the industry.

  • Micro or miniature drill bit is the smallest drill bits that come in size from 0.05 mm to 1.5 mm. Miniature drill bits are used for drilling holes in small items.
  • Letter drill bits are famous drill bits that contain alphabets. Their sizes are mentioned in alphabets “A” to “Z.” They come in sizes from 0.234 to 6.35 mm. Their main uses are drilling small holes in wood, plastic, or soft metal.
  • Fractional drill bits are considered the largest drill bits that come in sizes from 1/64 inch to ½ inch. These drill bits are used in drilling medium holes in different materials.
  • Metric drill bit sizes range from 0.5 mm to 13 mm. They are commonly used for drilling hard metals and concrete. You must check concrete drill bit sizes in mm before using them for concrete.
  • Spade drill bits are used for drilling large and flat holes from 1 to 6 inches. They are used for drill presses.
  • The masonry drill bit is a common size used for drilling holes in concrete. The masonry drill bit sizes in mm range from 3 mm to 16 mm, used in hammer drills.
  • Forstner drill bits come in sizes from ¼ to 2 inches and are used for flat-bottomed drilling holes.

How Do You Know What Size Drill Bit to Use?

To determine the size of a drill bit to use for a specific hole must ensure the following things:

  • Determine the hole size by measuring.
  • Select the required drill bit by checking from the package.
  • Also, consider the material you are drilling. If you have material such as wood, you will need a slightly larger drill than the hole.
  • Check different sizes of the drill bits with the holes to know the best-fit drill bit.
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How Do You Know What Size Drill Bit to Use for Wall Anchors?

To use a drill bit for wall anchors, you have to measure the size of the wall anchor first. After measuring the diameter of a wall anchor, choose the drill bit that is a little larger than the wall anchor.

It is also essential to remember that your drill bit should be masonry while you are drilling in the wall. Once you have chosen the drill bit, test it for the anchor to ensure you have chosen the right one. It is also good to read the manufacturer’s instructions to choose the best one quickly.

How Do You Know What Size Drill Bit to Use for Wall Plugs?

Measure the diameter of the wall plug or check for the package or instructions for choosing the right drill bit. However, once you have measured the diameter of the wall plug, choose a slightly larger drill bit to ensure you have a tight fit and proper drill bit.

How to Know What Size Drill Bit Is for the Screw?

Follow the simple steps below to know the correct size of a drill bit for a screw.

  • Read the screw product information about the required drill bit size.
  • If you do not have the information for the screw, then measure the screw diameter using a digital caliper.
  • Next, check the drill bit size chart; you can easily find it on the internet.
  • Use a drill bit set to know the correct drill bit size for the screw.

Frequently Asked Questions (FAQs)

What size is a 10 mm drill bit in standard?

A 10 mm drill bit is equivalent to a ⅜ or 0.375-inch standard-size drill bit.

What size is a 7 mm drill bit in standard?

A 7 mm drill bit is equivalent to a 9/32 or 0.2815-inch standard drill bit size.

What size is equivalent to a 6 mm drill bit in standard?

The standard drill bit of 15/64 or 0.2343 inches is equivalent to the 6 mm drill bit.

What is a 12 mm drill bit in standard?

12 mm size is equal to 21/64 or 0.328 inches in the standard drill bit.

Are drill bit numbers in mm?

Yes, drill bit numbers are in mm. The size of a drill bit is determined in mm, such as 3 mm, 6 mm, etc. They are also in inches but mostly come in mm.


The size of a drill bit is a crucial aspect of drilling projects. Understanding the common sizes of drill bits and their equivalent is a must. Standard drill bits mostly come with mm size specifications. So it is necessary to know the correct equivalents for choosing the right drill bit for a smooth drilling experience.

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