Standard drill bit sizes for CNC machining (conversion tables)

Top Level Intl.
November 23, 2021
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Introduction

In CNC machining manufacturing, we need to use both standard drill bits and custom drill bits. The tables below summarize the standard drill bit sizes which are used in CNC machining services. They are practical tables for your information in your CNC machining projects.

Table Of Contents

Introduction
Standard Metric Drill Bit Sizes
Fractional Inch Drill Bit Sizes
Wire Gauge Drill Bit Sizes

Standard Metric Drill Bit Sizes

Drill size	Diameter (in)	Drill size	Diameter (in)	Drill size	Diameter (in)	Drill size	Diameter (in)
0.05 mm	0.0020	4 mm	0.1575	8 mm	0.3150	20 mm	0.7874
0.1 mm	0.0039	4.1 mm	0.1614	8.1 mm	0.3189	20.5 mm	0.8071
0.2 mm	0.0079	4.2 mm	0.1654	8.2 mm	0.3228	21 mm	0.8268
0.3 mm	0.0118	4.3 mm	0.1693	8.3 mm	0.3268	21.5 mm	0.8465
0.4 mm	0.0158	4.4 mm	0.1732	8.4 mm	0.3307	22 mm	0.8661
0.5 mm	0.0197	4.5 mm	0.1772	8.5 mm	0.3347	22.5 mm	0.8858
0.6 mm	0.0236	4.6 mm	0.1811	8.6 mm	0.3386	23 mm	0.9055
0.7 mm	0.0276	4.7 mm	0.1850	8.7 mm	0.3425	23.5 mm	0.9252
0.8 mm	0.0315	4.8 mm	0.1890	8.8 mm	0.3465	24 mm	0.9449
0.9 mm	0.0354	4.9 mm	0.1929	8.9 mm	0.3504	24.5 mm	0.9646
1 mm	0.0394	5 mm	0.1969	9 mm	0.3543	25 mm	0.9843
1.1 mm	0.0433	5.1 mm	0.2008	9.1 mm	0.3583	25.5 mm	1.0039
1.2 mm	0.0472	5.2 mm	0.2047	9.2 mm	0.3622	26 mm	1.0236
1.3 mm	0.0512	5.3 mm	0.2087	9.3 mm	0.3661	26.5 mm	1.0433
1.4 mm	0.0551	5.4 mm	0.2126	9.4 mm	0.3701	27 mm	1.0630
1.5 mm	0.0591	5.5 mm	0.2165	9.5 mm	0.3740	27.5 mm	1.0827
1.6 mm	0.0630	5.6 mm	0.2205	9.6 mm	0.3780	28 mm	1.1024
1.7 mm	0.0669	5.7 mm	0.2244	9.7 mm	0.3819	28.5 mm	1.1221
1.8 mm	0.0709	5.8 mm	0.2284	9.8 mm	0.3858	29 mm	1.1417
1.9 mm	0.0748	5.9 mm	0.2323	9.9 mm	0.3898	29.5 mm	1.1614
2 mm	0.0787	6 mm	0.2362	10 mm	0.3937	30 mm	1.1811
2.1 mm	0.0827	6.1 mm	0.2402	10.5 mm	0.4134	30.5 mm	1.2008
2.2 mm	0.0866	6.2 mm	0.2441	11 mm	0.4331	31 mm	1.2205
2.3 mm	0.0906	6.3 mm	0.2480	11.5 mm	0.4528	31.5 mm	1.2402
2.4 mm	0.0945	6.4 mm	0.2520	12 mm	0.4724	32 mm	1.2598
2.5 mm	0.098	6.5 mm	0.2559	12.5 mm	0.4921	32.5 mm	1.2795
2.6 mm	0.1024	6.6 mm	0.2598	13 mm	0.5118	33 mm	1.2992
2.7 mm	0.1063	6.7 mm	0.2638	13.5 mm	0.5315	33.5 mm	1.3189
2.8 mm	0.1102	6.8 mm	0.2677	14 mm	0.5512	34 mm	1.3386
2.9 mm	0.1142	6.9 mm	0.2717	14.5 mm	0.5709	34.5 mm	1.3583
3 mm	0.1181	7 mm	0.2756	15 mm	0.5906	35 mm	1.3780
3.1 mm	0.1221	7.1 mm	0.2795	15.5 mm	0.6102	35.5 mm	1.3976
3.2 mm	0.1260	7.2 mm	0.2835	16 mm	0.6299	36 mm	1.4173
3.3 mm	0.1299	7.3 mm	0.2874	16.5 mm	0.6496	36.5 mm	1.4370
3.4 mm	0.1339	7.4 mm	0.2913	17 mm	0.6693	37 mm	1.4567
3.5 mm	0.1378	7.5 mm	0.2953	17.5 mm	0.6890	37.5 mm	1.4764
3.6 mm	0.1417	7.6 mm	0.2992	18 mm	0.7087	38 mm	1.4961
3.7 mm	0.1457	7.7 mm	0.3032	18.5 mm	0.7284
3.8 mm	0.1496	7.8 mm	0.3071	19 mm	0.7480
3.9 mm	0.153	7.9 mm	0.3110	19.5 mm	0.7677

Fractional Inch Drill Bit Sizes

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

Wire Gauge Drill Bit Sizes

Drill size	Diameter (in)	Diameter (mm)	Drill size	Diameter (in)	Diameter (mm)
#107	0.0019	0.0483	#4	0.0980	2.4892
#106	0.0023	0.0584	#39	0.0995	2.5273
#105	0.0027	0.0686	#38	0.1015	2.5781
#104	0.0031	0.0787	#37	0.1040	2.6416
#103	0.0035	0.0889	#36	0.1065	2.7051
#102	0.0039	0.0991	#35	0.1100	2.7940
#101	0.0043	0.1092	#34	0.1110	2.8194
#100	0.0047	0.1194	#33	0.1130	2.8702
#99	0.0051	0.1295	#32	0.1160	2.9464
#98	0.0055	0.1397	#31	0.1200	3.0480
#97	0.0059	0.1499	#30	0.1285	3.2639
#96	0.0063	0.1600	#29	0.1360	3.4544
#95	0.0067	0.1702	#28	0.1405	3.5687
#94	0.0071	0.1803	#27	0.1440	3.6576
#93	0.0075	0.1905	#26	0.1470	3.7338
#92	0.0079	0.2007	#25	0.1495	3.7973
#91	0.0083	0.2108	#24	0.1520	3.8608
#90	0.0087	0.2210	#23	0.1540	3.9116
#89	0.0091	0.2311	#22	0.1570	3.9878
#88	0.0095	0.2413	#21	0.1590	4.0386
#87	0.0100	0.2540	#20	0.1610	4.0894
#86	0.0105	0.2667	#19	0.1660	4.2164
#85	0.0110	0.2794	#18	0.1695	4.3053
#84	0.0115	0.2921	#17	0.1730	4.3942
#83	0.0120	0.3048	#16	0.1770	4.4958
#82	0.0125	0.3175	#15	0.1800	4.5720
#81	0.0130	0.3302	#14	0.1820	4.6228
#80	0.0135	0.3429	#13	0.1850	4.6990
#79	0.0145	0.3680	#12	0.1890	4.8006
#78	0.0160	0.4064	#11	0.1910	4.8514
#77	0.0180	0.4572	#10	0.1935	4.9149
#76	0.0200	0.5080	#9	0.1960	4.9784
#75	0.0210	0.5334	#8	0.1990	5.0546
#74	0.0225	0.5715	#7	0.2010	5.1054
#73	0.0240	0.6096	#6	0.2040	5.1816
#72	0.0250	0.6350	#5	0.2055	5.2197
#71	0.0260	0.6604	#4	0.2090	5.3086
#70	0.0280	0.7112	#3	0.2130	5.4102
#69	0.0292	0.7417	#2	0.2210	5.6134
#68	0.0310	0.7874	#1	0.2280	5.7912
#67	0.0320	0.8128	A	0.2340	5.9436
#66	0.0330	0.8382	B	0.2380	6.0452
#65	0.0350	0.8890	C	0.2420	6.1468
#64	0.0360	0.9144	D	0.2460	6.2484
#63	0.0370	0.9398	E	0.2500	6.3500
#62	0.0380	0.9652	F	0.2570	6.5278
#61	0.0390	0.9906	G	0.2610	6.6294
#60	0.0400	1.0160	H	0.2660	6.7564
#59	0.0410	1.0414	I	0.2720	6.9088
#58	0.0420	1.0668	J	0.2770	7.0358
57	0.0430	1.0922	K	0.2810	7.1374
#56	0.0465	1.1811	L	0.2900	7.3660
#55	0.0520	1.3208	M	0.2950	7.4930
#54	0.0550	1.3970	N	0.3020	7.6708
#53	0.0595	1.5113	O	0.3160	8.0264
#52	0.0635	1.6129	P	0.3230	8.2042
#51	0.0670	1.7018	Q	0.3320	8.4328
#50	0.0700	1.7780	R	0.3390	8.6106
#49	0.0730	1.8542	S	0.3480	8.8392
#48	0.0760	1.9304	T	0.3580	9.0932
#47	0.0785	1.9939	U	0.3680	9.3472
#46	0.0810	2.0574	V	0.3770	9.5758
#45	0.0820	2.0828	W	0.3860	9.8044
#44	0.0860	2.1844	X	0.3970	10.0838
#43	0.0890	2.2606	Y	0.4040	10.2616
#42	0.0935	2.3749	Z	0.4130	10.4902
#41	0.0960	2.4384

Thanks for reading. Top Level Intl. is an experienced CNC machining shop in China. We supply custom CNC Machined Parts and Progressive Cavity Pump Spare Parts. So we created this blog and shared some guides and acknowledge involved in. Hope it’s helpful to you. For any questions, feel free to contact us!