Drill Bit Sizes and Drill Chart

Drill bit sizes printed on set

Having the right drill bit sizes on hand for your particular repair or building task is essential for any seasoned carpenter or weekend-DIY’er.

Knowing just what size you need to use for the hole you’re making is also important.

It may not be totally evident at first glance.

Many times, we’re just trying to find out the alternative sizes available if you’re working with metric sizes (measured in millimeters) versus standard or empirical values (our familiar fractional inch variety).

TIP: Check out our full drill chart below for a quick reference to find all drill size equivalents.

Finally, getting the right size drill bit set in your greater tool “chest” will arm you for the various types of projects you’re doing.

We’ll discuss these in detail in this article.

Scroll down if you just need a quick reference using our drill chart.

How Many Drill Bit Sizes Are There?

First things first. If you were to look at the most all encompassing collection of multi-purpose, twist-type bits, how many drill bit sizes would there be?

Well, if you base your answer on how many size holes there are in the world, then there would be infinite amount of bits!

Thankfully, we can narrow it down a bit to some standard sized holes and bits.

For example, let’s look at the most common applications:

Everyday home repair and construction projects, hobby, marine, farming, woodworking, metal working, aircraft, arts and crafts, commercial building projects, machinery and more.

You get the point!

For each particular application area, you’re going to just see a few dozen or so relevant drill bit sizes.

Large set of bits with different types and sizes

In fact, most nice sets include anywhere from 12-30 pieces of standard drill bit sizes. (And much more when you factor in different types of bits).

Using our drill chart that follows below, you’ll get an idea of just how many sizes there are!

Types of Drill Bits

Various bit types exist for a wide variety of applications, and in particular what material you’re drilling into.

For the sake of simplicity, let’s look at a basic multi-purpose set.

One that could serve any of the above mentioned disciplines well.

Say, for example, a typical 29-piece set. In the following drill bit chart are the typical fractional sizes this kind of set would include.

This would generally apply to many drill bit types, such as black oxide, titanium, carbide, high-speed steel and masonry (concrete), to name a few.

Basic, twist-type drill bit sizes (fractional):

  • 1/16″
  • 5/64″
  • 3/32″
  • 7/64″
  • 1/8″
  • 9/64″
  • 5/32″
  • 11/64″
  • 3/16″
  • 13/64″
  • 7/32″
  • 15/64″
  • 1/4″
  • 17/64″
  • 9/32″
  • 19/64″
  • 5/16″
  • 21/64″
  • 11/32″
  • 23/64″
  • 3/8″
  • 25/64″
  • 13/32″
  • 27/64″
  • 7/16″
  • 29/64″
  • 15/32″
  • 31/64″
  • 1/2″

There are indeed larger sets. Specialty fasteners sometimes call for a size that would be considered uncommon.

Sets with even more varying drill bit sizes would include diameters smaller than 1/16″ or larger than 1-1/2″.

In between in these large tiny and large sizes are every equivalent bit size known to “man”, so you always have the exact size needed depending on what you’re project is calling for.

Here would be the standard drill bit sizes for spade bits (13-pieces):

  • 1/4″, 3/8″, 1/2″, 9/16″, 5/8″, 11/16″, 3/4″, 7/8″, 1″, 1-1/8″, 1-1/4″, 1-3/8″ and 1-1/2″

And sizes for step drill bits:

  • Range from 1/8″ to 1-3/8″

If you need drill bit sizes that are larger than 1″, you can often use a spade bit for wood and other soft materials.

To avoid break-outs and chipping, you can stick to bigger round-shank types.

or shank bits though, you’ll usually need a

  • 1/2; 33/64; 17/32; 35/64; 9/16; 37/64; 19/32; 39/64; 5/8; 41/64; 21/32; 43/64; 11/16; 45/64; 23/32; 47/64; 3/4; 49/64; 25/32; 51/64; 13/16; 53/64; 27/32; 55/64; 7/8; 57/64; 29/32; 59/64; 15/16; 61/64; 31/32; 63/64; 1; 1-1/8; 1-1/4; 1-3/8; 1-1/2

How Do You Know What Size Drill Bits You Need?

If you’re an average weekend-warrior, you’ve probably stared at a screw or bolt for a few moments and wondered what size drill bit you would need.

Over time, you get so that you can literally eye-ball it and make an educated guess.

But if you’re looking at a less common drill bit size, you need an aid to help you.

A drill bit size hole card can be very helpful for this. A simple plastic drill chart sheet with perfect round holes and markings on it lets you do a couple of things.

First, you can size screws simply by inserting them into a hole then reading the marking.

You can also size drill bits by pushing them through holes.

This is especially helpful if you can’t read the engraved size markings on the bits.

It’s also helpful to find the substitute bit size to cross over between metric and standard measurements.

How to Convert and Find Equivalent Bit Sizes

You can use the drill chart that follows this section to help convert sizes, or you can do the math yourself.

Drill bit size conversion chart

To make things just a little more complicated, not all drill bit sizes are in north american fractional measurements.

The metric system is used to define metric drill bit sizes as well.

If you have this set, or need to match, just use a simple formula to convert from metric to fractional inches, and vice versa:

  • Converting from millimeters into inches: Multiply by 0.039
  • Converting from inches to millimeters: Multiply by 25.4

Matching Screw Sizes

Sizing screw to drill bit size

If you’re curious what size drill bit you’ll need for a particular screw, use the following drill bit size chart:

Screw Size

  • #1
  • #2
  • #3
  • #4
  • #5
  • #6
  • #7
  • #8
  • #9
  • #10
  • #11
  • #12

Hole to clear screw

  • 5/64
  • 3/32
  • 7/64
  • 1/8
  • 1/8
  • 9/64
  • 5/32
  • 11/64
  • 11/64
  • 3/16
  • 3/16
  • 7/32

Drill Bit Size Gauge

Even better is to get yourself a drill bit gauge.

These handy cards can help you in a pinch, and can help you to quickly identify which size bit you’ll need based on the screw or hole size you need to drill out. Get one here!

 29-Hole Steel Drill Bit Gauge

Super handy bit size gauge

Best of all, they’re pretty inexpensive and will be something to have as part of your DIY toolbox for many years to come.

Drill Chart:

As promised, here are a few drill bit charts to help you quickly convert all standard drill bit sizes to their matching measurements.

If you’re tapping holes you’re pre-drilling you can check out our tap drill chart for specific size conversions.

Drill Chart for Gauge 47-96 (smallest to largest)

This chart lists the North American drill gauge sizes and converts them to their decimal equivalent in both inches and millimeters for metric sizes.

NOTE: Below these charts is the standard fractional size conversion drill chart.

Gauge Dec. (in.) Dec. (mm)  Gauge Dec. (in.) Dec. (mm)
960.00630.16 710.0260.66
950.00670.17 700.0280.711
940.00710.18 690.02920.742
930.00750.191 680.0310.787
920.00790.201 670.0320.813
910.00830.211 660.0330.838
900.00870.221 650.0350.889
890.00910.231 640.0360.914
880.00950.241 630.0370.94
870.010.254 620.0380.965
860.01050.267 610.0390.991
850.0110.279 600.041.016
840.01150.292 590.0411.041
830.0120.305 580.0421.067
820.01250.318 570.0431.092
810.0130.33 560.04651.181
800.01350.343 550.0521.321
790.01450.368 540.0551.397
780.0160.406 530.05951.511
770.0180.457 520.06351.613
760.020.508 510.0671.702
750.0210.533 500.071.778
740.02250.572 490.0731.854
730.0240.61 480.0761.93
720.0250.635 470.07851.994

 

Drill Chart for Gauge 1-46 (smallest to largest)

This chart rounds out the second half of these number gauge sizes down to #1, which is the largest drill bit size.

Gauge Dec. (in.) Dec. (mm)  Gauge Dec. (in.) Dec. (mm)
460.0812.057 230.1543.912
450.0822.083 220.1573.988
440.0862.184 210.1594.039
430.0892.261 200.1614.089
420.09352.375 190.1664.216
410.0962.438 180.16954.305
400.0982.489 170.1734.394
390.09952.527 160.1774.496
380.10152.578 150.184.572
370.1042.642 140.1824.623
360.10652.705 130.1854.699
350.112.794 120.1894.801
340.1112.819 110.1914.851
330.1132.87 100.19354.915
320.1162.946 90.1964.978
310.123.048 80.1995.055
300.12853.264 70.2015.105
290.1363.454 60.2045.182
280.14053.569 50.20555.22
270.1443.658 40.2095.309
260.1473.734 30.2135.41
250.14953.797 20.2215.613
240.1523.861 10.2285.791

 

Drill Chart for Gauge Letters (smallest to largest)

Letter gauge drill sizes are used primarily in North American with A starting with the smallest size working 26 size increments to Z.

Gauge Dec. (in.) Dec. (mm)  Gauge Dec. (in.) Dec. (mm)
A0.2345.944 N0.3027.671
B0.2386.045 O0.3168.026
C0.2426.147 P0.3238.204
D0.2466.248 Q0.3328.433
E0.256.35 R0.3398.611
F0.2576.528 S0.3488.839
G0.2616.629 T0.3589.093
H0.2666.756 U0.3689.347
I0.2726.909 V0.3779.576
J0.2777.036 W0.3869.804
K0.2817.137 X0.39710.08
L0.297.366 Y0.40410.26
M0.2957.493 Z0.41310.49

 

Drill Bit Size Chart: Fractional to Decimal & Metric (Small to Large)

The following drill chart covers the smallest standard drill diameter size of 1/64 to 21/32 and gives you the equivalent sizes in both decimal inches and millimeters.

Diam.Dec. (In.)Dec. (mm)   Diam.Dec. (In.)Dec. (mm) 
1/640.01560.3969 11/320.34388.7313
1/320.03130.7938 23/640.35949.1281
3/640.04691.1906 3/80.3759.525
1/160.06251.5875 25/640.39069.9219
5/640.07811.9844 13/320.406310.3188
3/320.09382.3813 27/640.421910.7156
7/640.10942.7781 7/160.437511.1125
1/80.1253.175 29/640.453111.5094
9/640.14063.5719 15/320.468811.9063
5/320.15633.9688 31/640.484412.3031
11/640.17194.3656 1/20.512.7
3/160.18754.7625 33/640.515613.0969
13/640.20315.1594 17/320.531313.4938
7/320.21885.5563 35/640.546913.8906
15/640.23445.9531 9/160.562514.2875
1/40.256.35 37/640.578114.6844
17/640.26566.7469 19/320.593815.0813
9/320.28137.1438 39/640.609415.4781
19/640.29697.5406 5/80.62515.875
5/160.31257.9375 41/640.640616.2719
21/640.32818.3344 21/320.656316.6688

 

This final drill chart covers the standard bit sizes from 43/64 to 1 27/64.

Diam.Dec. (In.)Dec. (mm)   Diam.Dec. (In.)Dec. (mm) 
43/640.671917.0656 1125.4
11/160.687517.4625 1 1/641.015625.7969
45/640.703117.8594 1 1/321.031326.1938
23/320.718818.2563 1 3/641.046926.5906
47/640.734418.6531 1 1/161.062526.9875
3/40.7519.05 1 7/641.109428.1781
49/640.765619.4469 1 1/81.12528.575
25/320.781319.8438 1 5/321.156329.3688
51/640.796920.2406 1 11/641.171929.7656
13/160.812520.6375 1 3/161.187530.1625
53/640.828121.0344 1 13/641.203130.5594
27/320.843821.4313 1 7/321.218830.9563
55/640.859421.8281 1 15/641.234431.3531
7/80.87522.225 1 9/321.281332.5438
57/640.890622.6219 1 19/641.296932.9406
29/320.906323.0188 1 5/161.312533.3375
59/640.921923.4156 1 21/641.328133.7344
15/160.937523.8125 1 11/321.343834.1313
61/640.953124.2094 1 23/641.359434.5281
31/320.968824.6063 1 13/321.406335.7188
63/640.984425.0031 1 27/641.421936.1156

 

More About Drill Bit Sets and Sizing

Some other helpful information to help you in your knowledge of drill bit sizes:

Fractional Sizing

Fractional sizing uses whole, half (1/2), quarter (1/4), eighth (1/8), sixteenths (1/16) and sixty-forths (1/64).

For example, something just above 31/64″ would be a half-inch, and anything above 63/64″ would be a 1-inch drill bit size.

Super Long Bits

Long drill bits for masonry

Long bit sizes have typical lengths of: 12″ or 18″ overall length. These are handy in situations where you need to drill through thick or multi-layered materials.

Professionals in the electrical industry for example will use these when running wires or cables through finished walls and ceilings.

Other contractors will use masonry bits in their hammer drills to bore through materials such as concrete, stones and bricks.

This is especially useful when creating a hole from the outside of your house to the interior. Lengths of up to 18″ or more may be needed.

Drill Bit Point Angles

The typical sizes of drill bit point angles are 115° or 118° (degrees).

When buying a good set, ensure it contains more than just one of the common (important) size drill bits.

Bits do break as they weaken from usage and high amounts of heat generated from friction.

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