Drill Bit Size Chart

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 Guide 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’!