Drill Bit Size Chart

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If you consider yourself a handyman of fine woodworking, exquisite metallurgy, and other fixing pursuits, you probably already know the sheer importance of being aware of different drill bit size chart and their immense importance.

Indeed, drill a hole in your drywall that’s too big for the nail or screw you designated for it, and now you have to either seal the hole or somehow make the screw in question thicker. Both of these scenarios have one thing in common – they’re annoying and will make your small project take longer than needed to finish. (Plus, your drywall has been compromised!)

Now, in this article, we’re going to provide you a brief guide on how to figure out what drill bit size you need, depending on different gauges you may want to use, and according to different metric systems.

Before we start, though, let’s review a couple of important matters related to drilling bits.

How to Choose Drill Bits

There are several parameters about choosing the right drill bit for the project at hand. For example, when it comes to figuring out the shape of the drill bits you’ll be using, the most important parameter to look into would be the material you’re working with.

In case you want to drill into wood, what you want to look for are drill bits that have a minute pointed tip at the end, while the rest is flat. This type of drill will drive hard into the wood and will be able to carve into it easily, and without overheating the wood too much. If you’re looking for some extra durability, you may want to get a package of titanium-coated drill bits.

Masonry drill bits have a sloped top so that they can drive into the concrete, cinder, or even tile with ease. (Well, drilling into masonry is never really easy, but it’s certainly much easier doing it with these specialized sloped drill bits.) Many masonry drill bit manufacturers also cover their bits with carbide to make them last longer and to further improve their toughness.

Last but not least, metal drill bits have an angled point with a sharp tip at its end. Usually, you can recognize them because they’re painted black. An interesting thing about these drill bits is that they come in a special series called HSS (which means ‘high-speed steel’) These will be better than just the regular drill bits, so if you’re looking for speed and durability, look for that HSS label, as well.

Drill Bit Chart for Gauge Letters

As you probably already know, there are several ways to classify drill bit sizes. One of the most commonly used in North America would be the so-called Letter way, which uses the alphabet to mark different sizes. (The chart starts with A, which is the smallest one, and ends with Z, the largest one.)

Gauge Dec. (in.) Dec. (mm)   Gauge Dec. (in.) Dec. (mm)
A 0.234 5.944   N 0.302 7.671
B 0.238 6.045   O 0.316 8.026
C 0.242 6.147   P 0.323 8.204
D 0.246 6.248   Q 0.332 8.433
E 0.25 6.35   R 0.339 8.611
F 0.257 6.528   S 0.348 8.839
G 0.261 6.629   T 0.358 9.093
H 0.266 6.756   U 0.368 9.347
I 0.272 6.909   V 0.377 9.576
J 0.277 7.036   W 0.386 9.804
K 0.281 7.137   X 0.397 10.08
L 0.29 7.366   Y 0.404 10.26
M 0.295 7.493   Z 0.413 10.49

Drill Chart for Gauge 1-96

Another way of representing the drill bit sizes would be to use numbers. The way this works is that 96 represents the smallest bit and then the largest one is at number 1. Here’s the chart for these two and all the sizes in between.

Gauge Dec. (in.) Dec. (mm)   Gauge Dec. (in.) Dec. (mm)
96 0.0063 0.16   46 0.081 2.057
95 0.0067 0.17   45 0.082 2.083
94 0.0071 0.18   44 0.086 2.184
93 0.0075 0.191   43 0.089 2.261
92 0.0079 0.201   42 0.0935 2.375
91 0.0083 0.211   41 0.096 2.438
90 0.0087 0.221   40 0.098 2.489
89 0.0091 0.231   39 0.0995 2.527
88 0.0095 0.241   38 0.1015 2.578
87 0.01 0.254   37 0.104 2.642
86 0.0105 0.267   36 0.1065 2.705
85 0.011 0.279   35 0.11 2.794
84 0.0115 0.292   34 0.111 2.819
83 0.012 0.305   33 0.113 2.87
82 0.0125 0.318   32 0.116 2.946
81 0.013 0.33   31 0.12 3.048
80 0.0135 0.343   30 0.1285 3.264
79 0.0145 0.368   29 0.136 3.454
78 0.016 0.406   28 0.1405 3.569
77 0.018 0.457   27 0.144 3.658
76 0.02 0.508   26 0.147 3.734
75 0.021 0.533   25 0.1495 3.797
74 0.0225 0.572   24 0.152 3.861
73 0.024 0.61   23 0.154 3.912
72 0.025 0.635   22 0.157 3.988
71 0.026 0.66   21 0.159 4.039
70 0.028 0.711   20 0.161 4.089
69 0.0292 0.742   19 0.166 4.216
68 0.031 0.787   18 0.1695 4.305
67 0.032 0.813   17 0.173 4.394
66 0.033 0.838   16 0.177 4.496
65 0.035 0.889   15 0.18 4.572
64 0.036 0.914   14 0.182 4.623
63 0.037 0.94   13 0.185 4.699
62 0.038 0.965   12 0.189 4.801
61 0.039 0.991   11 0.191 4.851
60 0.04 1.016   10 0.1935 4.915
59 0.041 1.041   9 0.196 4.978
58 0.042 1.067   8 0.199 5.055
57 0.043 1.092   7 0.201 5.105
56 0.0465 1.181   6 0.204 5.182
55 0.052 1.321   5 0.2055 5.22
54 0.055 1.397   4 0.209 5.309
53 0.0595 1.511   3 0.213 5.41
52 0.0635 1.613   2 0.221 5.613
51 0.067 1.702   1 0.228 5.791
50 0.07 1.778        
49 0.073 1.854        
48 0.076 1.93        
47 0.0785 1.994        

Drill Bit Size Chart – Fractions + Metric + Imperial System

In the chart below, you can see the different values expressed in three common ways. (Well, depending on where you live.) The first column is dedicated to fractions, while the following two represent the same value expressed in the imperial and metric systems. The smallest value starts at 1/64 and it goes all the way to the largest one at 21/32.

Diam. Dec. (In.) Dec. (mm)   Diam. Dec. (In.) Dec. (mm)
1/64 0.0156 0.3969   11/32 0.3438 8.7313
1/32 0.0313 0.7938   23/64 0.3594 9.1281
3/64 0.0469 1.1906   3/8 0.375 9.525
1/16 0.0625 1.5875   25/64 0.3906 9.9219
5/64 0.0781 1.9844   13/32 0.4063 10.3188
3/32 0.0938 2.3813   27/64 0.4219 10.7156
7/64 0.1094 2.7781   7/16 0.4375 11.1125
1/8 0.125 3.175   29/64 0.4531 11.5094
9/64 0.1406 3.5719   15/32 0.4688 11.9063
5/32 0.1563 3.9688   31/64 0.4844 12.3031
11/64 0.1719 4.3656   1/2 0.5 12.7
3/16 0.1875 4.7625   33/64 0.5156 13.0969
13/64 0.2031 5.1594   17/32 0.5313 13.4938
7/32 0.2188 5.5563   35/64 0.5469 13.8906
15/64 0.2344 5.9531   9/16 0.5625 14.2875
1/4 0.25 6.35   37/64 0.5781 14.6844
17/64 0.2656 6.7469   19/32 0.5938 15.0813
9/32 0.2813 7.1438   39/64 0.6094 15.4781
19/64 0.2969 7.5406   5/8 0.625 15.875
5/16 0.3125 7.9375   41/64 0.6406 16.2719
21/64 0.3281 8.3344   21/32 0.6563 16.6688

This chart can help designers who design drill bits with SolidWorks software or other software

So, these are the drill bit charts most commonly used in North America. Hope this article helped you find the right size of bit drill for the project at hand. Best of luck with your handyman’s projects and keep on rockin’!