How to Choose What Size Drill Bit To Use

Drilling is a must-have skill for both DIY home improvement and large-scale tasks. Therefore, it’s important that you choose the right size bill bit for each drilling task.

Having holes with the correct diameter is crucial, especially if you use screws or other fasteners. Choosing the right drill bit size is the first step in getting the job done correctly.

How Do I Know What Size Drill Bit to Use?

To determine the size of the drill bit, you need to calculate the diameter of the hole that needs drilling. Drill bits with sizes between 1 mm and 20 mm in diameter are the most common drill bits

The drill hole size should be the same size as the screw's central core diameter or slightly smaller. 

Here are the suggested pilot hole sizes based on the size of the screw you will use. 

Screw Size

Pilot hole size for hardwoods

Pilot hole size for softwood































Remember to examine the screw and drill bit first before filling to avoid costly mistakes. If the hole is too large, it will compromise the connection between the materials and the screw.


How Do You Match a Drill Bit to a Screw?

One of the easiest ways to determine drill bit size is by examining the screws you are going to use. To do this, you should compare the diameter of your drill bit to the diameter of the screw to see if it's the best fit. Having the right size allows the head of the screw to penetrate the material without splitting the grain, while allowing the threads of the screw to join two boards together.


Should a Drill Bit Be The Same Size As A Screw?

The drill bit should be almost the same size as the screw's center core, not the thread or spiral part. Some believe that drilling tiny pilot holes allows the screw to fit securely, resulting in a more stable bond. However, pilot holes that are too small might split or crack the object being drilled.

Do All Drill Bits Fit All Drills?

Drill bits will fit on a drill as long as the shank size and diameter are the same. However, fitting drill bits from different brands will depend on two things; the shank's type and diameter. 

The shank is usually round or square, depending on the brand and type. Therefore, the shank must be the same size and shape as the drill's chuck to fit the drill bit. 

There are two distinct circular shanks: SDS and SDS Max, used in Hammer Drill Bits and Chisels. The SDS and SDS Plus have a 10-millimeter shank, whereas the SDS Max has an 18-millimeter shank. In addition, there are a lot of adapters that let you use different types and sizes of drill bits.

How to Determine the Size of Your Drill Bit For An Anchor

Using a drill bit that is the same size as the anchor's body is recommended. It is essential to use a drill bit large enough to drill a hole in the wall, but small enough that you can insert the anchor with your thumb without using a power tool.

To ensure that the drill bit is the same size as the anchor minus the flange, hold the drill up to the anchor and measure the distance from its end to your drill bit.

Anchors are available in various styles, sizes, and holding capacities that determine the maximum weight of an object that may be safely hung on it. 

To help you decide which drill bit size is right for your anchor, take a look at the below table:



1/4″ x 1-3/8″


5/16″ x 1-1/2″


5/16″ x 2-1/2″


3/8″ x 1-7/8″


3/8″ x 3″


3/8″ x 4″


1/2″ x 2-1/4″


1/2″ x 2-3/4″


1/2″ x 3″


1/2″ x 4″


5/8″ x 3″


5/8″ x 4-1/4″


3/4″ x 4-1/4″




What Size Drill Bit To Use For Drywall Anchors

The diameter of the hole depends on the size of the drywall anchors. Therefore, comparing the drill bit's shank measurement with the anchor's front before drilling is necessary. Ideally, it should be the same diameter as the screw or slightly larger. The anchor's diameter is typically indicated on its box.


What Size Drill Bit To Use For Concrete Anchors and Toggle Bolts

Concrete anchors and toggle bolts holes should be the same size. For example, 3/8 concrete anchor should have a 3/8 hole or be slightly larger. However, there is no need to use a drill bit for self-tap drywall anchors.

Types Of Drill Bits

Here are the most common drill bits available:

  • Twist Drill Bit - This is the most common type of drill bit, which is used for a variety of home improvement, and construction applications. They can be used on metal, wood, and plastic.
  • Brad and Pilot Point Bit - This is the best drill bit for DIY wood projects, as it has an exit hole which is formed by a W-shape centered point. It is also suitable for constructing furniture, cabinets, and other woodworking projects.
  • Countersink Drill Bit - This is an excellent tool for general woodworking and cabinetry. They are designed for use in countersunk holes. A countersink makes a conical hole that fits the angle of the screw.
  • Step Drill Bit - This drill bit is perfect for drilling pilot holes in wood and metal. Allows drilling holes of varied sizes with a single drill bit.
  • Masonry Drill Bit - Suitable for concrete, brick, and masonry. It’s used for construction and repair of homes and It works best with a hammer drill.


Buying The Right Size Drill Bit

Fasteners like screws and anchors are critical in small and large-scale building projects to secure various components together. For a more secure fastener, selecting the correct drill bit size is vital. Depending on your needs, you can buy a single drill bit or a whole set. Find the best drill bits for screws in our online store.

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