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Engineer Tools: Standard Drill Bit Size Charts

Drill Bits - Drill Bit Size Charts
Engineer Tools: Standard Drill Bit Size Charts
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Standard Drill Bit Sizes for CNC Machining

These conversion tables provide standard drill bit sizes (metric, fractional inch, and wire gauges) that are commonly used in CNC machining to reduce manufacturing costs by eliminating the need for custom tooling.

Standard Metric Drill Bit Sizes

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

Drill Size (in) Diameter (in) Diameter (mm)
1/64
0.0156
0.3969
1/32
0.0313
0.7938
3/64
0.0469
1.1906
1/16
0.0625
1.5875
5/64
0.0781
1.9844
3/32
0.0938
2.3813
7/64
0.1094
2.7781
1/8
0.1250
3.1750
9/64
0.1406
3.5719
5/32
0.1563
3.9688
11/64
0.1719
4.3656
3/16
0.1875
4.7625
13/64
0.2031
5.1594
7/32
0.2188
5.5563
15/64
0.2344
5.9531
1/4
0.2500
6.3500
17/64
0.2656
6.7469
9/32
0.2813
7.1438
19/64
0.2969
7.5406
5/16
0.3125
7.9375
21/64
0.3281
8.3344
11/32
0.3438
8.7313
23/64
0.3594
9.1281
3/8
0.3750
9.5250
25/64
0.3906
9.9219
13/32
0.4063
10.3188
27/64
0.4219
10.7156
7/16
0.4375
11.1125
29/64
0.4531
11.5094
15/32
0.4688
11.9063
31/64
0.4844
12.3031
1/2
0.5000
12.7000
33/64
0.5156
13.0969
17/32
0.5313
13.4938
35/64
0.5469
13.8906
9/16
0.5625
14.2875
37/64
0.5781
14.6844
19/32
0.5938
15.0813
39/64
0.6094
15.4781
5/8
0.6250
15.8750
41/64
0.6406
16.2719
43/64
0.6719
17.0656
11/16
0.6875
17.4625
45/64
0.7031
17.8594
23/32
0.7188
18.2563
47/64
0.7344
18.6531
3/4
0.7500
19.0500
49/64
0.7656
19.4469
25/32
0.7813
19.8438
51/64
0.7969
20.2406
13/16
0.8125
20.6375
53/64
0.8281
21.0344
27/32
0.8438
21.4313
55/64
0.8594
21.8281
7/8
0.8750
22.2250
57/64
0.8906
22.6219
29/32
0.9063
32.0188
21/23
0.9130
23.1913
59/64
0.9219
23.4156
15/16
0.9375
23.8125
61/64
0.9531
24.2094
31/32
0.9688
24.6063
63/64
0.9844
25.0031
1
1.0000
25.4000
1 1/64
1.0156
25.7969
1 1/32
1.0313
26.1938
1 3/64
1.0469
26.5906
1 1/16
1.0625
26.9875
1 5/64
1.0781
27.3844
1 3/32
1.0938
27.7813
1 7/64
1.1094
28.1781
1 1/8
1.1250
28.5750
1 9/64
1.1406
28.9719
1 5/32
1.1563
29.3688
1 11/64
1.1719
29.7656
1 3/16
1.1875
30.1625
1 13/64
1.2031
30.5594
1 7/32
1.2188
30.9563
1 15/64
1.2344
31.3531
1 1/4
1.2500
31.7500
1 17/64
1.2656
32.1469
1 9/32
1.2813
32.5438
1 19/64
1.2969
32.9406
1 5/16
1.3125
33.3375
1 21/64
1.3281
33.7344
1 11/32
1.3438
34.1313
1 23/64
1.3594
34.5281
1 3/8
1.3750
34.9250
1 25/64
1.3906
35.3219
1 13/32
1.4063
35.7188
1 27/64
1.4219
36.1156
1 7/16
1.4375
36.5125
1 29/64
1.4531
36.9094
1 15/32
1.4688
37.3063
1 31/64
1.4844
37.7031
1 1/2
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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The content on this blog post is for informational purposes only. Prototek does not make any declaration or guarantee, whether expressed or implied, regarding the information’s accuracy, completeness, or validity. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be assumed to represent what will be delivered by third-party suppliers or us. It’s crucial to note that buyers seeking quotes for parts are responsible for defining the specific requirements for their project.

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