Standard drill bit sizes for CNC machining (conversion tables)

Tables of the standard drill bit sizes (metric, fractional inch, and wire gauge) commonly used in CNC machining.

Written by Alkaios Bournias Varotsis

Standard Drill Bit Sizes for CNC machining (Conversion Tables)

Introduction

The tables below summarize the standard drill bit sizes used in CNC machining.

Standard metric drill bit sizes

Drill size	Diameter (in)
0.05 mm	0.0020
0.1 mm	0.0039
0.2 mm	0.0079
0.3 mm	0.0118
0.4 mm	0.0158
0.5 mm	0.0197
0.6 mm	0.0236
0.7 mm	0.0276
0.8 mm	0.0315
0.9 mm	0.0354
1 mm	0.0394
1.1 mm	0.0433
1.2 mm	0.0472
1.3 mm	0.0512
1.4 mm	0.0551
1.5 mm	0.0591
1.6 mm	0.0630
1.7 mm	0.0669
1.8 mm	0.0709
1.9 mm	0.0748
2 mm	0.0787
2.1 mm	0.0827
2.2 mm	0.0866
2.3 mm	0.0906
2.4 mm	0.0945
2.5 mm	0.0984
2.6 mm	0.1024
2.7 mm	0.1063
2.8 mm	0.1102
2.9 mm	0.1142
3 mm	0.1181
3.1 mm	0.1221
3.2 mm	0.1260
3.3 mm	0.1299
3.4 mm	0.1339
3.5 mm	0.1378
3.6 mm	0.1417
3.7 mm	0.1457
3.8 mm	0.1496
3.9 mm	0.1535
4 mm	0.1575
4.1 mm	0.1614
4.2 mm	0.1654
4.3 mm	0.1693
4.4 mm	0.1732
4.5 mm	0.1772
4.6 mm	0.1811
4.7 mm	0.1850
4.8 mm	0.1890
4.9 mm	0.1929
5 mm	0.1969
5.1 mm	0.2008
5.2 mm	0.2047
5.3 mm	0.2087
5.4 mm	0.2126
5.5 mm	0.2165
5.6 mm	0.2205
5.7 mm	0.2244
5.8 mm	0.2284
5.9 mm	0.2323
6 mm	0.2362
6.1 mm	0.2402
6.2 mm	0.2441
6.3 mm	0.2480
6.4 mm	0.2520
6.5 mm	0.2559
6.6 mm	0.2598
6.7 mm	0.2638
6.8 mm	0.2677
6.9 mm	0.2717
7 mm	0.2756
7.1 mm	0.2795
7.2 mm	0.2835
7.3 mm	0.2874
7.4 mm	0.2913
7.5 mm	0.2953
7.6 mm	0.2992
7.7 mm	0.3032
7.8 mm	0.3071
7.9 mm	0.3110
8 mm	0.3150
8.1 mm	0.3189
8.2 mm	0.3228
8.3 mm	0.3268
8.4 mm	0.3307
8.5 mm	0.3347
8.6 mm	0.3386
8.7 mm	0.3425
8.8 mm	0.3465
8.9 mm	0.3504
9 mm	0.3543
9.1 mm	0.3583
9.2 mm	0.3622
9.3 mm	0.3661
9.4 mm	0.3701
9.5 mm	0.3740
9.6 mm	0.3780
9.7 mm	0.3819
9.8 mm	0.3858
9.9 mm	0.3898
10 mm	0.3937
10.5 mm	0.4134
11 mm	0.4331
11.5 mm	0.4528
12 mm	0.4724
12.5 mm	0.4921
13 mm	0.5118
13.5 mm	0.5315
14 mm	0.5512
14.5 mm	0.5709
15 mm	0.5906
15.5 mm	0.6102
16 mm	0.6299
16.5 mm	0.6496
17 mm	0.6693
17.5 mm	0.6890
18 mm	0.7087
18.5 mm	0.7284
19 mm	0.7480
19.5 mm	0.7677
20 mm	0.7874
20.5 mm	0.8071
21 mm	0.8268
21.5 mm	0.8465
22 mm	0.8661
22.5 mm	0.8858
23 mm	0.9055
23.5 mm	0.9252
24 mm	0.9449
24.5 mm	0.9646
25 mm	0.9843
25.5 mm	1.0039
26 mm	1.0236
26.5 mm	1.0433
27 mm	1.0630
27.5 mm	1.0827
28 mm	1.1024
28.5 mm	1.1221
29 mm	1.1417
29.5 mm	1.1614
30 mm	1.1811
30.5 mm	1.2008
31 mm	1.2205
31.5 mm	1.2402
32 mm	1.2598
32.5 mm	1.2795
33 mm	1.2992
33.5 mm	1.3189
34 mm	1.3386
34.5 mm	1.3583
35 mm	1.3780
35.5 mm	1.3976
36 mm	1.4173
36.5 mm	1.4370
37 mm	1.4567
37.5 mm	1.4764
38 mm	1.4961

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Fractional inch drill bit sizes

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

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Wire gauge drill bit sizes

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
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

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