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).

drill bit size chart
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

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Table of Content of Drill Bit Size Chart

Drill Bit Size Chart

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Metric Conversion Drill Bit Size Chart

Metric Drill sizeDiameter (in)Diameter (mm)
0.05 mm0.00200.0500
0.1 mm0.00390.1000
0.2 mm0.00790.2000
0.3 mm0.01180.3000
0.4 mm0.01580.4000
0.5 mm0.01970.5000
0.6 mm0.02360.6000
0.7 mm0.02760.7000
0.8 mm0.03150.8000
0.9 mm0.03540.9000
1 mm0.03941.0000
1.1 mm0.04331.1000
1.2 mm0.04721.2000
1.3 mm0.05121.3000
1.4 mm0.05511.4000
1.5 mm0.05911.5000
1.6 mm0.06301.6000
1.7 mm0.06691.7000
1.8 mm0.07091.8000
1.9 mm0.07481.9000
2 mm0.07872.0000
2.1 mm0.08272.1000
2.2 mm0.08662.2000
2.3 mm0.09062.3000
2.4 mm0.09452.4000
2.5 mm0.09842.5000
2.6 mm0.10242.6000
2.7 mm0.10632.7000
2.8 mm0.11022.8000
2.9 mm0.11422.9000
3 mm0.11813.0000
3.1 mm0.12213.1000
3.2 mm0.12603.2000
3.3 mm0.12993.3000
3.4 mm0.13393.4000
3.5 mm0.13783.5000
3.6 mm0.14173.6000
3.7 mm0.14573.7000
3.8 mm0.14963.8000
3.9 mm0.15353.9000
4 mm0.15754.0000
4.1 mm0.16144.1000
4.2 mm0.16544.2000
4.3 mm0.16934.3000
4.4 mm0.17324.4000
4.5 mm0.17724.5000
4.6 mm0.18114.6000
4.7 mm0.18504.7000
4.8 mm0.18904.8000
4.9 mm0.19294.9000
5 mm0.19695.0000
5.1 mm0.20085.1000
5.2 mm0.20475.2000
5.3 mm0.20875.3000
5.4 mm0.21265.4000
5.5 mm0.21655.5000
5.6 mm0.22055.6000
5.7 mm0.22445.7000
5.8 mm0.22845.8000
5.9 mm0.23235.9000
6 mm0.23626.0000
6.1 mm0.24026.1000
6.2 mm0.24416.2000
6.3 mm0.24806.3000
6.4 mm0.25206.4000
6.5 mm0.25596.5000
6.6 mm0.25986.6000
6.7 mm0.26386.7000
6.8 mm0.26776.8000
6.9 mm0.27176.9000
7 mm0.27567.0000
7.1 mm0.27957.1000
7.2 mm0.28357.2000
7.3 mm0.28747.3000
7.4 mm0.29137.4000
7.5 mm0.29537.5000
7.6 mm0.29927.6000
7.7 mm0.30327.7000
7.8 mm0.30717.8000
7.9 mm0.31107.9000
8 mm0.31508.0000
8.1 mm0.31898.1000
8.2 mm0.32288.2000
8.3 mm0.32688.3000
8.4 mm0.33078.4000
8.5 mm0.33478.5000
8.6 mm0.33868.6000
8.7 mm0.34258.7000
8.8 mm0.34658.8000
8.9 mm0.35048.9000
9 mm0.35439.0000
9.1 mm0.35839.1000
9.2 mm0.36229.2000
9.3 mm0.36619.3000
9.4 mm0.37019.4000
9.5 mm0.37409.5000
9.6 mm0.37809.6000
9.7 mm0.38199.7000
9.8 mm0.38589.8000
9.9 mm0.38989.9000
10 mm0.393710.0000
10.5 mm0.413410.5000
11 mm0.433111.0000
11.5 mm0.452811.5000
12 mm0.472412.0000
12.5 mm0.492112.5000
13 mm0.511813.0000
13.5 mm0.531513.5000
14 mm0.551214.0000
14.5 mm0.570914.5000
15 mm0.590615.0000
15.5 mm0.610215.5000
16 mm0.629916.0000
16.5 mm0.649616.5000
17 mm0.669317.0000
17.5 mm0.689017.5000
18 mm0.708718.0000
18.5 mm0.728418.5000
19 mm0.748019.0000
19.5 mm0.767719.5000
20 mm0.787420.0000
20.5 mm0.807120.5000
21 mm0.826821.0000
21.5 mm0.846521.5000
22 mm0.866122.0000
22.5 mm0.885822.5000
23 mm0.905523.0000
23.5 mm0.925223.5000
24 mm0.944924.0000
24.5 mm0.964624.5000
25 mm0.984325.0000
25.5 mm1.003925.5000
26 mm1.023626.0000
26.5 mm1.043326.5000
27 mm1.063027.0000
27.5 mm1.082727.5000
28 mm1.102428.0000
28.5 mm1.122128.5000
29 mm1.141729.0000
29.5 mm1.161429.5000
30 mm1.181130.0000
30.5 mm1.200830.5000
31 mm1.220531.0000
31.5 mm1.240231.5000
32 mm1.259832.0000
32.5 mm1.279532.5000
33 mm1.299233.0000
33.5 mm1.318933.5000
34 mm1.338634.0000
34.5 mm1.358334.5000
35 mm1.378035.0000
35.5 mm1.397635.5000
36 mm1.417336.0000
36.5 mm1.437036.5000
37 mm1.456737.0000
37.5 mm1.476437.5000
38 mm1.496138.0000

Gauge Number Drill Bit Sizes

Gauge Drill sizeDiameter (in)Diameter (mm)
#1070.00190.0483
#1060.00230.0584
#1050.00270.0686
#1040.00310.0787
#1030.00350.0889
#1020.00390.0991
#1010.00430.1092
#1000.00470.1194
#990.00510.1295
#980.00550.1397
#970.00590.1499
#960.00630.1600
#950.00670.1702
#940.00710.1803
#930.00750.1905
#920.00790.2007
#910.00830.2108
#900.00870.2210
#890.00910.2311
#880.00950.2413
#870.01000.2540
#860.01050.2667
#850.01100.2794
#840.01150.2921
#830.01200.3048
#820.01250.3175
#810.01300.3302
#800.01350.3429
#790.01450.3680
#780.01600.4064
#770.01800.4572
#760.02000.5080
#750.02100.5334
#740.02250.5715
#730.02400.6096
#720.02500.6350
#710.02600.6604
#700.02800.7112
#690.02920.7417
#680.03100.7874
#670.03200.8128
#660.03300.8382
#650.03500.8890
#640.03600.9144
#630.03700.9398
#620.03800.9652
#610.03900.9906
#600.04001.0160
#590.04101.0414
#580.04201.0668
#570.04301.0922
#560.04651.1811
#550.05201.3208
#540.05501.3970
#530.05951.5113
#520.06351.6129
#510.06701.7018
#500.07001.7780
#490.07301.8542
#480.07601.9304
#470.07851.9939
#460.08102.0574
#450.08202.0828
#440.08602.1844
#430.08902.2606
#420.09352.3749
#410.09602.4384
#400.09802.4892
#390.09952.5273
#380.10152.5781
#370.10402.6416
#360.10652.7051
#350.11002.7940
#340.11102.8194
#330.11302.8702
#320.11602.9464
#310.12003.0480
#300.12853.2639
#290.13603.4544
#280.14053.5687
#270.14403.6576
#260.14703.7338
#250.14953.7973
#240.15203.8608
#230.15403.9116
#220.15703.9878
#210.15904.0386
#200.16104.0894
#190.16604.2164
#180.16954.3053
#170.17304.3942
#160.17704.4958
#150.18004.5720
#140.18204.6228
#130.18504.6990
#120.18904.8006
#110.19104.8514
#100.19354.9149
#90.19604.9784
#80.19905.0546
#70.20105.1054
#60.20405.1816
#50.20555.2197
#40.20905.3086
#30.21305.4102
#20.22105.6134
#10.22805.7912
Picking the Right Drill Bit Size for a Screw by Bob’s Wood Stuff

Fractional Drill Bit Sizes

Fractional Drill sizeDiameter (in)Diameter (mm)
1/64 in0.01560.3969
1/32 in0.03130.7938
3/64 in0.04691.1906
1/16 in0.06251.5875
5/64 in0.07811.9844
3/32 in0.09382.3813
7/64 in0.10942.7781
1/8 in0.12503.1750
9/64 in0.14063.5719
5/32 in0.15633.9688
11/64 in0.17194.3656
3/16 in0.18754.7625
13/64 in0.20315.1594
7/32 in0.21885.5563
15/64 in0.23445.9531
1/4 in0.25006.3500
17/64 in0.26566.7469
9/32 in0.28137.1438
19/64 in0.29697.5406
5/16 in0.31257.9375
21/64 in0.32818.3344
11/32 in0.34388.7313
23/64 in0.35949.1281
3/8 in0.37509.5250
25/64 in0.39069.9219
13/32 in0.406310.3188
27/64 in0.421910.7156
7/16 in0.437511.1125
29/64 in0.453111.5094
15/32 in0.468811.9063
31/64 in0.484412.3031
1/2 in0.500012.7000
33/64 in0.515613.0969
17/32 in0.531313.4938
35/64 in0.546913.8906
9/16 in0.562514.2875
37/64 in0.578114.6844
19/32 in0.593815.0813
39/64 in0.609415.4781
5/8 in0.625015.8750
41/64 in0.640616.2719
43/64 in0.671917.0656
11/16 in0.687517.4625
45/64 in0.703117.8594
23/32 in0.718818.2563
47/64 in0.734418.6531
3/4 in0.750019.0500
49/64 in0.765619.4469
25/32 in0.781319.8438
51/64 in0.796920.2406
13/16 in0.812520.6375
53/64 in0.828121.0344
27/32 in0.843821.4313
55/64 in0.859421.8281
7/8 in0.875022.2250
57/64 in0.890622.6219
29/32 in0.906323.0188
21/23 in0.913023.1913
59/64 in0.921923.4156
15/16 in0.937523.8125
61/64 in0.953124.2094
31/32 in0.968824.6063
63/64 in0.984425.0031
1 in1.000025.4000
1 1/64 in1.015625.7969
1 1/32 in1.031326.1938
1 3/64 in1.046926.5906
1 1/16 in1.062526.9875
1 5/64 in1.078127.3844
1 3/32 in1.093827.7813
1 7/64 in1.109428.1781
1 1/8 in1.125028.5750
1 9/64 in1.140628.9719
1 5/32 in1.156329.3688
1 11/64 in1.171929.7656
1 3/16 in1.187530.1625
1 13/64 in1.203130.5594
1 7/32 in1.218830.9563
1 15/64 in1.234431.3531
1 1/4 in1.250031.7500
1 17/64 in1.265632.1469
1 9/32 in1.281332.5438
1 19/64 in1.296932.9406
1 5/16 in1.312533.3375
1 21/64 in1.328133.7344
1 11/32 in1.343834.1313
1 23/64 in1.359434.5281
1 3/8 in1.375034.9250
1 25/64 in1.390635.3219
1 13/32 in1.406335.7188
1 27/64 in1.421936.1156
1 7/16 in1.437536.5125
1 29/64 in1.453136.9094
1 15/32 in1.468837.3063
1 31/64 in1.484437.7031
1 1/2 in1.500038.1000

Letter Drill Bit Sizes

Drill sizeDiameter (in)Diameter (mm)
A0.23405.9436
B0.23806.0452
C0.24206.1468
D0.24606.2484
E0.25006.3500
F0.25706.5278
G0.26106.6294
H0.26606.7564
I0.27206.9088
J0.27707.0358
K0.28107.1374
L0.29007.3660
M0.29507.4930
N0.30207.6708
O0.31608.0264
P0.32308.2042
Q0.33208.4328
R0.33908.6106
S0.34808.8392
T0.35809.0932
U0.36809.3472
V0.37709.5758
W0.38609.8044
X0.397010.0838
Y0.404010.2616
Z0.413010.4902

Center Drill Bit Sizes

SizeDrill Diameter inchesDrill Diameter mm
5/00.010in0.254 mm
4/00.015 in0.381 mm
3/00.020 in0.508 mm
2/00.025 in0.635 mm
01/32 in0.794 mm
13/64 in1.191 mm
25/64 in1.984 mm
37/64 in2.778 mm
41/8 in3.175 mm
9/64 in3.572 mm
53/16 in4.763 mm
67/32 in5.556 mm
71/4 in6.350 mm
85/16 in7.938 mm

How to Choose the Right Drill Bit Size

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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.

drill bit size chart
Image Source: buildsearch.com.au

The right drill bit size to pre-drill holes explained (video)

Choosing The Right Size Pre Drill Bit by Training Hands Academy

The Best Type of Drill Bit for You

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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)

Drill bit Sizing explained by Peter Jones

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

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