Drill Bit Size Chart and Different Types in Metric, Gauge Size and More…

October 4, 2022October 15, 2023 by Thomas Vandepitte

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 and Different Types in Metric, Gauge Size and More... size-charts.com — 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

Drill Bit Size Chart

Metric Conversion Drill Bit Size Chart

Metric Drill size	Diameter (in)	Diameter (mm)
0.05 mm	0.0020	0.0500
0.1 mm	0.0039	0.1000
0.2 mm	0.0079	0.2000
0.3 mm	0.0118	0.3000
0.4 mm	0.0158	0.4000
0.5 mm	0.0197	0.5000
0.6 mm	0.0236	0.6000
0.7 mm	0.0276	0.7000
0.8 mm	0.0315	0.8000
0.9 mm	0.0354	0.9000
1 mm	0.0394	1.0000
1.1 mm	0.0433	1.1000
1.2 mm	0.0472	1.2000
1.3 mm	0.0512	1.3000
1.4 mm	0.0551	1.4000
1.5 mm	0.0591	1.5000
1.6 mm	0.0630	1.6000
1.7 mm	0.0669	1.7000
1.8 mm	0.0709	1.8000
1.9 mm	0.0748	1.9000
2 mm	0.0787	2.0000
2.1 mm	0.0827	2.1000
2.2 mm	0.0866	2.2000
2.3 mm	0.0906	2.3000
2.4 mm	0.0945	2.4000
2.5 mm	0.0984	2.5000
2.6 mm	0.1024	2.6000
2.7 mm	0.1063	2.7000
2.8 mm	0.1102	2.8000
2.9 mm	0.1142	2.9000
3 mm	0.1181	3.0000
3.1 mm	0.1221	3.1000
3.2 mm	0.1260	3.2000
3.3 mm	0.1299	3.3000
3.4 mm	0.1339	3.4000
3.5 mm	0.1378	3.5000
3.6 mm	0.1417	3.6000
3.7 mm	0.1457	3.7000
3.8 mm	0.1496	3.8000
3.9 mm	0.1535	3.9000
4 mm	0.1575	4.0000
4.1 mm	0.1614	4.1000
4.2 mm	0.1654	4.2000
4.3 mm	0.1693	4.3000
4.4 mm	0.1732	4.4000
4.5 mm	0.1772	4.5000
4.6 mm	0.1811	4.6000
4.7 mm	0.1850	4.7000
4.8 mm	0.1890	4.8000
4.9 mm	0.1929	4.9000
5 mm	0.1969	5.0000
5.1 mm	0.2008	5.1000
5.2 mm	0.2047	5.2000
5.3 mm	0.2087	5.3000
5.4 mm	0.2126	5.4000
5.5 mm	0.2165	5.5000
5.6 mm	0.2205	5.6000
5.7 mm	0.2244	5.7000
5.8 mm	0.2284	5.8000
5.9 mm	0.2323	5.9000
6 mm	0.2362	6.0000
6.1 mm	0.2402	6.1000
6.2 mm	0.2441	6.2000
6.3 mm	0.2480	6.3000
6.4 mm	0.2520	6.4000
6.5 mm	0.2559	6.5000
6.6 mm	0.2598	6.6000
6.7 mm	0.2638	6.7000
6.8 mm	0.2677	6.8000
6.9 mm	0.2717	6.9000
7 mm	0.2756	7.0000
7.1 mm	0.2795	7.1000
7.2 mm	0.2835	7.2000
7.3 mm	0.2874	7.3000
7.4 mm	0.2913	7.4000
7.5 mm	0.2953	7.5000
7.6 mm	0.2992	7.6000
7.7 mm	0.3032	7.7000
7.8 mm	0.3071	7.8000
7.9 mm	0.3110	7.9000
8 mm	0.3150	8.0000
8.1 mm	0.3189	8.1000
8.2 mm	0.3228	8.2000
8.3 mm	0.3268	8.3000
8.4 mm	0.3307	8.4000
8.5 mm	0.3347	8.5000
8.6 mm	0.3386	8.6000
8.7 mm	0.3425	8.7000
8.8 mm	0.3465	8.8000
8.9 mm	0.3504	8.9000
9 mm	0.3543	9.0000
9.1 mm	0.3583	9.1000
9.2 mm	0.3622	9.2000
9.3 mm	0.3661	9.3000
9.4 mm	0.3701	9.4000
9.5 mm	0.3740	9.5000
9.6 mm	0.3780	9.6000
9.7 mm	0.3819	9.7000
9.8 mm	0.3858	9.8000
9.9 mm	0.3898	9.9000
10 mm	0.3937	10.0000
10.5 mm	0.4134	10.5000
11 mm	0.4331	11.0000
11.5 mm	0.4528	11.5000
12 mm	0.4724	12.0000
12.5 mm	0.4921	12.5000
13 mm	0.5118	13.0000
13.5 mm	0.5315	13.5000
14 mm	0.5512	14.0000
14.5 mm	0.5709	14.5000
15 mm	0.5906	15.0000
15.5 mm	0.6102	15.5000
16 mm	0.6299	16.0000
16.5 mm	0.6496	16.5000
17 mm	0.6693	17.0000
17.5 mm	0.6890	17.5000
18 mm	0.7087	18.0000
18.5 mm	0.7284	18.5000
19 mm	0.7480	19.0000
19.5 mm	0.7677	19.5000
20 mm	0.7874	20.0000
20.5 mm	0.8071	20.5000
21 mm	0.8268	21.0000
21.5 mm	0.8465	21.5000
22 mm	0.8661	22.0000
22.5 mm	0.8858	22.5000
23 mm	0.9055	23.0000
23.5 mm	0.9252	23.5000
24 mm	0.9449	24.0000
24.5 mm	0.9646	24.5000
25 mm	0.9843	25.0000
25.5 mm	1.0039	25.5000
26 mm	1.0236	26.0000
26.5 mm	1.0433	26.5000
27 mm	1.0630	27.0000
27.5 mm	1.0827	27.5000
28 mm	1.1024	28.0000
28.5 mm	1.1221	28.5000
29 mm	1.1417	29.0000
29.5 mm	1.1614	29.5000
30 mm	1.1811	30.0000
30.5 mm	1.2008	30.5000
31 mm	1.2205	31.0000
31.5 mm	1.2402	31.5000
32 mm	1.2598	32.0000
32.5 mm	1.2795	32.5000
33 mm	1.2992	33.0000
33.5 mm	1.3189	33.5000
34 mm	1.3386	34.0000
34.5 mm	1.3583	34.5000
35 mm	1.3780	35.0000
35.5 mm	1.3976	35.5000
36 mm	1.4173	36.0000
36.5 mm	1.4370	36.5000
37 mm	1.4567	37.0000
37.5 mm	1.4764	37.5000
38 mm	1.4961	38.0000

Gauge Number Drill Bit Sizes

Gauge Drill size	Diameter (in)	Diameter (mm)
#107	0.0019	0.0483
#106	0.0023	0.0584
#105	0.0027	0.0686
#104	0.0031	0.0787
#103	0.0035	0.0889
#102	0.0039	0.0991
#101	0.0043	0.1092
#100	0.0047	0.1194
#99	0.0051	0.1295
#98	0.0055	0.1397
#97	0.0059	0.1499
#96	0.0063	0.1600
#95	0.0067	0.1702
#94	0.0071	0.1803
#93	0.0075	0.1905
#92	0.0079	0.2007
#91	0.0083	0.2108
#90	0.0087	0.2210
#89	0.0091	0.2311
#88	0.0095	0.2413
#87	0.0100	0.2540
#86	0.0105	0.2667
#85	0.0110	0.2794
#84	0.0115	0.2921
#83	0.0120	0.3048
#82	0.0125	0.3175
#81	0.0130	0.3302
#80	0.0135	0.3429
#79	0.0145	0.3680
#78	0.0160	0.4064
#77	0.0180	0.4572
#76	0.0200	0.5080
#75	0.0210	0.5334
#74	0.0225	0.5715
#73	0.0240	0.6096
#72	0.0250	0.6350
#71	0.0260	0.6604
#70	0.0280	0.7112
#69	0.0292	0.7417
#68	0.0310	0.7874
#67	0.0320	0.8128
#66	0.0330	0.8382
#65	0.0350	0.8890
#64	0.0360	0.9144
#63	0.0370	0.9398
#62	0.0380	0.9652
#61	0.0390	0.9906
#60	0.0400	1.0160
#59	0.0410	1.0414
#58	0.0420	1.0668
#57	0.0430	1.0922
#56	0.0465	1.1811
#55	0.0520	1.3208
#54	0.0550	1.3970
#53	0.0595	1.5113
#52	0.0635	1.6129
#51	0.0670	1.7018
#50	0.0700	1.7780
#49	0.0730	1.8542
#48	0.0760	1.9304
#47	0.0785	1.9939
#46	0.0810	2.0574
#45	0.0820	2.0828
#44	0.0860	2.1844
#43	0.0890	2.2606
#42	0.0935	2.3749
#41	0.0960	2.4384
#40	0.0980	2.4892
#39	0.0995	2.5273
#38	0.1015	2.5781
#37	0.1040	2.6416
#36	0.1065	2.7051
#35	0.1100	2.7940
#34	0.1110	2.8194
#33	0.1130	2.8702
#32	0.1160	2.9464
#31	0.1200	3.0480
#30	0.1285	3.2639
#29	0.1360	3.4544
#28	0.1405	3.5687
#27	0.1440	3.6576
#26	0.1470	3.7338
#25	0.1495	3.7973
#24	0.1520	3.8608
#23	0.1540	3.9116
#22	0.1570	3.9878
#21	0.1590	4.0386
#20	0.1610	4.0894
#19	0.1660	4.2164
#18	0.1695	4.3053
#17	0.1730	4.3942
#16	0.1770	4.4958
#15	0.1800	4.5720
#14	0.1820	4.6228
#13	0.1850	4.6990
#12	0.1890	4.8006
#11	0.1910	4.8514
#10	0.1935	4.9149
#9	0.1960	4.9784
#8	0.1990	5.0546
#7	0.2010	5.1054
#6	0.2040	5.1816
#5	0.2055	5.2197
#4	0.2090	5.3086
#3	0.2130	5.4102
#2	0.2210	5.6134
#1	0.2280	5.7912

Picking the Right Drill Bit Size for a Screw by Bob’s Wood Stuff

Fractional Drill Bit Sizes

Fractional Drill size	Diameter (in)	Diameter (mm)
1/64 in	0.0156	0.3969
1/32 in	0.0313	0.7938
3/64 in	0.0469	1.1906
1/16 in	0.0625	1.5875
5/64 in	0.0781	1.9844
3/32 in	0.0938	2.3813
7/64 in	0.1094	2.7781
1/8 in	0.1250	3.1750
9/64 in	0.1406	3.5719
5/32 in	0.1563	3.9688
11/64 in	0.1719	4.3656
3/16 in	0.1875	4.7625
13/64 in	0.2031	5.1594
7/32 in	0.2188	5.5563
15/64 in	0.2344	5.9531
1/4 in	0.2500	6.3500
17/64 in	0.2656	6.7469
9/32 in	0.2813	7.1438
19/64 in	0.2969	7.5406
5/16 in	0.3125	7.9375
21/64 in	0.3281	8.3344
11/32 in	0.3438	8.7313
23/64 in	0.3594	9.1281
3/8 in	0.3750	9.5250
25/64 in	0.3906	9.9219
13/32 in	0.4063	10.3188
27/64 in	0.4219	10.7156
7/16 in	0.4375	11.1125
29/64 in	0.4531	11.5094
15/32 in	0.4688	11.9063
31/64 in	0.4844	12.3031
1/2 in	0.5000	12.7000
33/64 in	0.5156	13.0969
17/32 in	0.5313	13.4938
35/64 in	0.5469	13.8906
9/16 in	0.5625	14.2875
37/64 in	0.5781	14.6844
19/32 in	0.5938	15.0813
39/64 in	0.6094	15.4781
5/8 in	0.6250	15.8750
41/64 in	0.6406	16.2719
43/64 in	0.6719	17.0656
11/16 in	0.6875	17.4625
45/64 in	0.7031	17.8594
23/32 in	0.7188	18.2563
47/64 in	0.7344	18.6531
3/4 in	0.7500	19.0500
49/64 in	0.7656	19.4469
25/32 in	0.7813	19.8438
51/64 in	0.7969	20.2406
13/16 in	0.8125	20.6375
53/64 in	0.8281	21.0344
27/32 in	0.8438	21.4313
55/64 in	0.8594	21.8281
7/8 in	0.8750	22.2250
57/64 in	0.8906	22.6219
29/32 in	0.9063	23.0188
21/23 in	0.9130	23.1913
59/64 in	0.9219	23.4156
15/16 in	0.9375	23.8125
61/64 in	0.9531	24.2094
31/32 in	0.9688	24.6063
63/64 in	0.9844	25.0031
1 in	1.0000	25.4000
1 1/64 in	1.0156	25.7969
1 1/32 in	1.0313	26.1938
1 3/64 in	1.0469	26.5906
1 1/16 in	1.0625	26.9875
1 5/64 in	1.0781	27.3844
1 3/32 in	1.0938	27.7813
1 7/64 in	1.1094	28.1781
1 1/8 in	1.1250	28.5750
1 9/64 in	1.1406	28.9719
1 5/32 in	1.1563	29.3688
1 11/64 in	1.1719	29.7656
1 3/16 in	1.1875	30.1625
1 13/64 in	1.2031	30.5594
1 7/32 in	1.2188	30.9563
1 15/64 in	1.2344	31.3531
1 1/4 in	1.2500	31.7500
1 17/64 in	1.2656	32.1469
1 9/32 in	1.2813	32.5438
1 19/64 in	1.2969	32.9406
1 5/16 in	1.3125	33.3375
1 21/64 in	1.3281	33.7344
1 11/32 in	1.3438	34.1313
1 23/64 in	1.3594	34.5281
1 3/8 in	1.3750	34.9250
1 25/64 in	1.3906	35.3219
1 13/32 in	1.4063	35.7188
1 27/64 in	1.4219	36.1156
1 7/16 in	1.4375	36.5125
1 29/64 in	1.4531	36.9094
1 15/32 in	1.4688	37.3063
1 31/64 in	1.4844	37.7031
1 1/2 in	1.5000	38.1000

Letter Drill Bit Sizes

Drill size	Diameter (in)	Diameter (mm)
A	0.2340	5.9436
B	0.2380	6.0452
C	0.2420	6.1468
D	0.2460	6.2484
E	0.2500	6.3500
F	0.2570	6.5278
G	0.2610	6.6294
H	0.2660	6.7564
I	0.2720	6.9088
J	0.2770	7.0358
K	0.2810	7.1374
L	0.2900	7.3660
M	0.2950	7.4930
N	0.3020	7.6708
O	0.3160	8.0264
P	0.3230	8.2042
Q	0.3320	8.4328
R	0.3390	8.6106
S	0.3480	8.8392
T	0.3580	9.0932
U	0.3680	9.3472
V	0.3770	9.5758
W	0.3860	9.8044
X	0.3970	10.0838
Y	0.4040	10.2616
Z	0.4130	10.4902

Center Drill Bit Sizes

Size	Drill Diameter inches	Drill Diameter mm
5/0	0.010in	0.254 mm
4/0	0.015 in	0.381 mm
3/0	0.020 in	0.508 mm
2/0	0.025 in	0.635 mm
0	1/32 in	0.794 mm
1	3/64 in	1.191 mm
2	5/64 in	1.984 mm
3	7/64 in	2.778 mm
4	1/8 in	3.175 mm
4½	9/64 in	3.572 mm
5	3/16 in	4.763 mm
6	7/32 in	5.556 mm
7	1/4 in	6.350 mm
8	5/16 in	7.938 mm

How to Choose the Right Drill Bit Size

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

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