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Fraction
Letter
Metric
Wire Gauge
FRACTION DRILL 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
0.125
3.175
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
0.25
6.35
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
0.375
9.525
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
0.5
12.7
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
0.625
15.875
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
0.75
19.05
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
0.875
22.225
57/64 in
0.8906
22.6219
29/32 in
0.9063
23.0188
21/23 in
0.913
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
25.4
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
1.125
28.575
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
1.25
31.75
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
1.375
34.925
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
1.5
38.1
LETTER DRILL SIZES
Drill size
Diameter (in)
Diameter (mm)
A
0.234
5.9436
B
0.238
6.0452
C
0.242
6.1468
D
0.246
6.2484
E
0.25
6.35
F
0.257
6.5278
G
0.261
6.6294
H
0.266
6.7564
I
0.272
6.9088
J
0.277
7.0358
K
0.281
7.1374
L
0.29
7.366
M
0.295
7.493
N
0.302
7.6708
O
0.316
8.0264
P
0.323
8.2042
Q
0.332
8.4328
R
0.339
8.6106
S
0.348
8.8392
T
0.358
9.0932
U
0.368
9.3472
V
0.377
9.5758
W
0.386
9.8044
X
0.397
10.0838
Y
0.404
10.2616
Z
0.413
10.4902
METRIC DRILL SIZES
Drill size
Diameter (in)
Diameter (mm)
0.05 mm
0.002
0.05
0.1 mm
0.0039
0.1
0.2 mm
0.0079
0.2
0.3 mm
0.0118
0.3
0.4 mm
0.0158
0.4
0.5 mm
0.0197
0.5
0.6 mm
0.0236
0.6
0.7 mm
0.0276
0.7
0.8 mm
0.0315
0.8
0.9 mm
0.0354
0.9
1 mm
0.0394
1
1.1 mm
0.0433
1.1
1.2 mm
0.0472
1.2
1.3 mm
0.0512
1.3
1.4 mm
0.0551
1.4
1.5 mm
0.0591
1.5
1.6 mm
0.063
1.6
1.7 mm
0.0669
1.7
1.8 mm
0.0709
1.8
1.9 mm
0.0748
1.9
2 mm
0.0787
2
2.1 mm
0.0827
2.1
2.2 mm
0.0866
2.2
2.3 mm
0.0906
2.3
2.4 mm
0.0945
2.4
2.5 mm
0.0984
2.5
2.6 mm
0.1024
2.6
2.7 mm
0.1063
2.7
2.8 mm
0.1102
2.8
2.9 mm
0.1142
2.9
3 mm
0.1181
3
3.1 mm
0.1221
3.1
3.2 mm
0.126
3.2
3.3 mm
0.1299
3.3
3.4 mm
0.1339
3.4
3.5 mm
0.1378
3.5
3.6 mm
0.1417
3.6
3.7 mm
0.1457
3.7
3.8 mm
0.1496
3.8
3.9 mm
0.1535
3.9
4 mm
0.1575
4
4.1 mm
0.1614
4.1
4.2 mm
0.1654
4.2
4.3 mm
0.1693
4.3
4.4 mm
0.1732
4.4
4.5 mm
0.1772
4.5
4.6 mm
0.1811
4.6
4.7 mm
0.185
4.7
4.8 mm
0.189
4.8
4.9 mm
0.1929
4.9
5 mm
0.1969
5
5.1 mm
0.2008
5.1
5.2 mm
0.2047
5.2
5.3 mm
0.2087
5.3
5.4 mm
0.2126
5.4
5.5 mm
0.2165
5.5
5.6 mm
0.2205
5.6
5.7 mm
0.2244
5.7
5.8 mm
0.2284
5.8
5.9 mm
0.2323
5.9
6 mm
0.2362
6
6.1 mm
0.2402
6.1
6.2 mm
0.2441
6.2
6.3 mm
0.248
6.3
6.4 mm
0.252
6.4
6.5 mm
0.2559
6.5
6.6 mm
0.2598
6.6
6.7 mm
0.2638
6.7
6.8 mm
0.2677
6.8
6.9 mm
0.2717
6.9
7 mm
0.2756
7
7.1 mm
0.2795
7.1
7.2 mm
0.2835
7.2
7.3 mm
0.2874
7.3
7.4 mm
0.2913
7.4
7.5 mm
0.2953
7.5
7.6 mm
0.2992
7.6
7.7 mm
0.3032
7.7
7.8 mm
0.3071
7.8
7.9 mm
0.311
7.9
8 mm
0.315
8
8.1 mm
0.3189
8.1
8.2 mm
0.3228
8.2
8.3 mm
0.3268
8.3
8.4 mm
0.3307
8.4
8.5 mm
0.3347
8.5
8.6 mm
0.3386
8.6
8.7 mm
0.3425
8.7
8.8 mm
0.3465
8.8
8.9 mm
0.3504
8.9
9 mm
0.3543
9
9.1 mm
0.3583
9.1
9.2 mm
0.3622
9.2
9.3 mm
0.3661
9.3
9.4 mm
0.3701
9.4
9.5 mm
0.374
9.5
9.6 mm
0.378
9.6
9.7 mm
0.3819
9.7
9.8 mm
0.3858
9.8
9.9 mm
0.3898
9.9
10 mm
0.3937
10
10.5 mm
0.4134
10.5
11 mm
0.4331
11
11.5 mm
0.4528
11.5
12 mm
0.4724
12
12.5 mm
0.4921
12.5
13 mm
0.5118
13
13.5 mm
0.5315
13.5
14 mm
0.5512
14
14.5 mm
0.5709
14.5
15 mm
0.5906
15
15.5 mm
0.6102
15.5
16 mm
0.6299
16
16.5 mm
0.6496
16.5
17 mm
0.6693
17
17.5 mm
0.689
17.5
18 mm
0.7087
18
18.5 mm
0.7284
18.5
19 mm
0.748
19
19.5 mm
0.7677
19.5
20 mm
0.7874
20
20.5 mm
0.8071
20.5
21 mm
0.8268
21
21.5 mm
0.8465
21.5
22 mm
0.8661
22
22.5 mm
0.8858
22.5
23 mm
0.9055
23
23.5 mm
0.9252
23.5
24 mm
0.9449
24
24.5 mm
0.9646
24.5
25 mm
0.9843
25
25.5 mm
1.0039
25.5
26 mm
1.0236
26
26.5 mm
1.0433
26.5
27 mm
1.063
27
27.5 mm
1.0827
27.5
28 mm
1.1024
28
28.5 mm
1.1221
28.5
29 mm
1.1417
29
29.5 mm
1.1614
29.5
30 mm
1.1811
30
30.5 mm
1.2008
30.5
31 mm
1.2205
31
31.5 mm
1.2402
31.5
32 mm
1.2598
32
32.5 mm
1.2795
32.5
33 mm
1.2992
33
33.5 mm
1.3189
33.5
34 mm
1.3386
34
34.5 mm
1.3583
34.5
35 mm
1.378
35
35.5 mm
1.3976
35.5
36 mm
1.4173
36
36.5 mm
1.437
36.5
37 mm
1.4567
37
37.5 mm
1.4764
37.5
38 mm
1.4961
38
Wire Gauge Charts
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
0.16
#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
0.221
#89
0.0091
0.2311
#88
0.0095
0.2413
#87
0.01
0.254
#86
0.0105
0.2667
#85
0.011
0.2794
#84
0.0115
0.2921
#83
0.012
0.3048
#82
0.0125
0.3175
#81
0.013
0.3302
#80
0.0135
0.3429
#79
0.0145
0.368
#78
0.016
0.4064
#77
0.018
0.4572
#76
0.02
0.508
#75
0.021
0.5334
#74
0.0225
0.5715
#73
0.024
0.6096
#72
0.025
0.635
#71
0.026
0.6604
#70
0.028
0.7112
#69
0.0292
0.7417
#68
0.031
0.7874
#67
0.032
0.8128
#66
0.033
0.8382
#65
0.035
0.889
#64
0.036
0.9144
#63
0.037
0.9398
#62
0.038
0.9652
#61
0.039
0.9906
#60
0.04
1.016
#59
0.041
1.0414
#58
0.042
1.0668
#57
0.043
1.0922
#56
0.0465
1.1811
#55
0.052
1.3208
#54
0.055
1.397
#53
0.0595
1.5113
#52
0.0635
1.6129
#51
0.067
1.7018
#50
0.07
1.778
#49
0.073
1.8542
#48
0.076
1.9304
#47
0.0785
1.9939
#46
0.081
2.0574
#45
0.082
2.0828
#44
0.086
2.1844
#43
0.089
2.2606
#42
0.0935
2.3749
#41
0.096
2.4384
#40
0.098
2.4892
#39
0.0995
2.5273
#38
0.1015
2.5781
#37
0.104
2.6416
#36
0.1065
2.7051
#35
0.11
2.794
#34
0.111
2.8194
#33
0.113
2.8702
#32
0.116
2.9464
#31
0.12
3.048
#30
0.1285
3.2639
#29
0.136
3.4544
#28
0.1405
3.5687
#27
0.144
3.6576
#26
0.147
3.7338
#25
0.1495
3.7973
#24
0.152
3.8608
#23
0.154
3.9116
#22
0.157
3.9878
#21
0.159
4.0386
#20
0.161
4.0894
#19
0.166
4.2164
#18
0.1695
4.3053
#17
0.173
4.3942
#16
0.177
4.4958
#15
0.18
4.572
#14
0.182
4.6228
#13
0.185
4.699
#12
0.189
4.8006
#11
0.191
4.8514
#10
0.1935
4.9149
#9
0.196
4.9784
#8
0.199
5.0546
#7
0.201
5.1054
#6
0.204
5.1816
#5
0.2055
5.2197
#4
0.209
5.3086
#3
0.213
5.4102
#2
0.221
5.6134
#1
0.228
5.7912
The drill size chart provides a list of standard size drill bits in several measurement systems, including fractional, metric, wire gauge number, and letter.
The decimal equivalents of the diameters are shown in both English and Metric units.
Fractional sizes are measured in inches, while metric sizes are measured in millimeters.
The wire gauge and letter systems refer to tool diameters that increase as the wire gauge decreases from #107 to #1 and then continues from A to Z.
The drill size chart contains tools up to 1.5 inches in diameter, but larger tools are also commonly used.