Drill Bit Size Chart (Metric-Imperial Equivalents)

For your convenience, we’ve compiled a simplified chart of drill bit sizes.
drill bit size chart

We trust that the information below is self-explanatory and straightforward.

Gauge Sizing Metric / SI Imperial / US
Number / Letter Size Millimeters Fractional Inches Fractional Inches (Reduced) Decimal Inches
--- 0.010 --- --- 0.0004
104 0.080 --- --- 0.0031
103 0.090 --- --- 0.0035
102 --- --- --- 0.0039
--- 0.100 --- --- 0.0039
101 0.110 --- --- 0.0043
100 0.120 --- --- 0.0047
99 0.130 --- --- 0.0051
98 0.140 --- --- 0.0055
97 0.150 --- --- 0.0059
96 0.160 --- --- 0.0063
95 0.170 --- --- 0.0067
94 0.180 --- --- 0.0071
93 0.190 --- --- 0.0075
--- 0.198 1/128 --- 0.0078
92 0.201 --- --- 0.0079
91 0.210 --- --- 0.0083
90 0.220 --- --- 0.0087
89 0.230 --- --- 0.0091
88 0.240 --- --- 0.0095
--- 0.250 --- --- 0.0098
87 0.254 --- --- 0.0100
--- 0.260 --- --- 0.0102
86 0.270 --- --- 0.0105
85 0.280 --- --- 0.0110
84 0.290 --- --- 0.0115
--- 0.300 --- --- 0.0118
83 0.305 --- --- 0.0120
82 0.318 --- --- 0.0125
81 0.330 --- --- 0.0130
80 0.343 --- --- 0.0135
79 0.368 --- --- 0.0145
--- 0.397 1/64 --- 0.0156
78 0.406 --- --- 0.0160
77 0.457 --- --- 0.0180
--- 0.500 --- --- 0.0197
76 0.508 --- --- 0.0200
75 0.533 --- --- 0.0210
74 0.572 --- --- 0.0225
73 0.610 --- --- 0.0240
72 0.635 --- --- 0.0250
71 0.660 --- --- 0.0260
70 0.710 --- --- 0.0280

69		 0.742 --- --- 0.0292
--- 0.750 --- --- 0.0295
68 0.787 --- --- 0.0310
--- 0.794 2/64 1/32 0.0312
67 0.813 --- --- 0.0320
66 0.838 --- --- 0.0330
65 0.889 --- --- 0.0350
64 0.914 --- --- 0.0360
63 0.940 --- --- 0.0370
62 0.965 --- --- 0.0380
61 0.991 --- --- 0.0390
--- 1.000 --- --- 0.0394
60 1.016 --- --- 0.0400
59 1.041 --- --- 0.0410
58 1.067 --- --- 0.0420
57 1.092 --- --- 0.0430
56 1.181 --- --- 0.0465
--- 1.191 3/64 --- 0.0469
--- 1.250 --- --- 0.0492
55 1.321 --- --- 0.0520
54 1.397 --- --- 0.0550
--- 1.500 --- --- 0.0591
53 1.511 --- --- 0.0595
--- 1.588 4/64   1/16 0.0625
52 1.613 --- --- 0.0635
51 1.702 --- --- 0.0670
--- 1.750 --- --- 0.0689
50 1.778 --- --- 0.0700
--- 1.800 --- --- 0.0709
--- 1.850 --- --- 0.0728
49 1.854 --- --- 0.0730
48 1.930 --- --- 0.0760
--- 1.984   5/64 --- 0.0781
47 1.994 --- --- 0.0785
--- 2.000 --- --- 0.0787
46 2.057 --- --- 0.0810
45 2.083 --- --- 0.0820
44 2.184 --- --- 0.0860
--- 2.250 --- --- 0.0886
43 2.261 --- --- 0.0890
42 2.375 --- --- 0.0935
--- 2.381 6/64   3/32 0.0938
41 2.438 --- --- 0.0960
--- 2.450 --- --- 0.0965
40 2.489 --- --- 0.0980
--- 2.500 --- --- 0.0984
39 2.527 --- --- 0.0995
38 2.578 --- --- 0.1015
37 2.642 --- --- 0.1040
36 2.705 --- --- 0.1065
--- 2.750 --- --- 0.1083
--- 2.778   7/64 --- 0.1094
35 2.794 --- --- 0.1100
34 2.819 --- --- 0.1110
33 2.870 --- --- 0.1130
32 2.946 --- --- 0.1160
--- 3.000 --- --- 0.1181
31 3.048 --- --- 0.1200
--- 3.175 8/64   1/8  0.1250
--- 3.250 --- --- 0.1280
30 3.264 --- --- 0.1285
29 3.454 --- --- 0.1360
--- 3.500 --- --- 0.1378
28 3.569 --- --- 0.1405
--- 3.572   9/64 --- 0.1406
27 3.658 --- --- 0.1440
26 3.734 --- --- 0.1470
--- 3.750 --- --- 0.1476
25 3.797 --- --- 0.1495
24 3.861 --- --- 0.1520
23 3.912 --- --- 0.1540
--- 3.969 10/64   5/32 0.1562
22 3.988 --- --- 0.1570
--- 4.000 --- --- 0.1575
21 4.039 --- --- 0.1590
20 4.089 --- --- 0.1610
19 4.216 --- --- 0.1660
--- 4.250 --- --- 0.1673
18 4.305 --- --- 0.1695
--- 4.366 11/64 --- 0.1720
17 4.394 --- --- 0.1730
16 4.496 --- --- 0.1770
--- 4.500 --- --- 0.1772
15 4.572 --- --- 0.1800
14 4.623 --- --- 0.1820
13 4.469 --- --- 0.1850
--- 4.750 --- --- 0.1870
--- 4.763 12/64   3/16 0.1875
12 4.800 --- --- 0.1890
11 4.850 --- --- 0.1910
10 4.915 --- --- 0.1935
9 4.978 --- --- 0.1960
--- 5.000 --- --- 0.1969
8 5.055 --- --- 0.1990
7 5.105 --- --- 0.2010
--- 5.159 13/64 --- 0.2031
6 5.182 --- --- 0.2040
5 5.220 --- --- 0.2055
--- 5.250 --- --- 0.2067
4 5.309 --- --- 0.2090
3 5.410 --- --- 0.2130
--- 5.500 --- --- 0.2165
---   14/64   7/32 0.2188
2 5.613 --- --- 0.2210
--- 5.750 --- --- 0.2264
1 5.791 --- --- 0.2280
A 5.944 --- --- 0.2340
--- 5.953 15/64 --- 0.2344
--- 6.000 --- --- 0.2362
B 6.045 --- --- 0.2380
--- 6.100 --- --- 0.2402
C 6.147 --- --- 0.2420
--- 6.200 --- --- 0.2441
D 6.248 --- --- 0.2460
--- 6.250 --- --- 0.2461
E 6.350 16/64   1/4  0.2500
--- 6.500 --- --- 0.2559
F 6.528 --- --- 0.2570
--- 6.600 --- --- 0.2598
G 6.629 --- --- 0.2610
--- 6.747 17/64 --- 0.2656
--- 6.750 --- --- 0.2657
H 6.756 --- --- 0.2660
--- 6.800 --- --- 0.2677
I 6.909 --- --- 0.2720
--- 7.000 --- --- 0.2756
J 7.036 --- --- 0.2770
--- 7.100 --- --- 0.2795
K 7.137 --- --- 0.2810
--- 7.144 18/64   9/32 0.2813
--- 7.250 --- --- 0.2854
--- 7.300 --- --- 0.2874
L 7.366 --- --- 0.2900
--- 7.400 --- --- 0.2913
M  7.493 --- --- 0.2950
--- 7.500 --- --- 0.2953
--- 7.541 19/64 --- 0.2969
--- 7.600 --- --- 0.2992
N 7.671 --- --- 0.3020
--- 7.750 --- --- 0.3051
--- 7.938 20/64   5/16 0.3125
--- 8.000 --- --- 0.3150
O 8.026 --- --- 0.3160
--- 8.100 --- --- 0.3189
--- 8.200 --- --- 0.3228
P 8.204 --- --- 0.3230
--- 8.250 --- --- 0.3248
--- 8.300 --- --- 0.3268
--- 8.334 21/64 --- 0.3281
Q 8.433 --- --- 0.3320
--- 8.500 --- --- 0.3346
R 8.611 --- --- 0.3390
--- 8.700 --- --- 0.3425
--- 8.731 22/64 11/32 0.3438
--- 8.750 --- --- 0.3445
S 8.839 --- --- 0.3480
--- 9.000 --- --- 0.3543
T 9.093 --- --- 0.3580
--- 9.128 23/64 --- 0.3594
--- 9.250 --- --- 0.3642
U 9.347 --- --- 0.3680
--- 9.500 --- --- 0.3740
--- 9.525 24/64   3/8  0.3750
V 9.576 --- --- 0.3770
--- 9.600 --- --- 0.3780
--- 9.700 --- --- 0.3819
--- 9.750 --- --- 0.3839
--- 9.800 --- --- 0.3858
W 9.804 --- --- 0.3860
--- 9.922 25/64 --- 0.3906
--- 10.000 --- --- 0.3937
X 10.080 --- --- 0.3970
--- 10.084 --- --- 0.4016
Y 10.260 --- --- 0.4040
--- 10.490 26/64 13/32 0.4063
Z 10.490 --- --- 0.4130
--- 10.500 --- --- 0.4134
--- 10.716 27/64 --- 0.4219
--- 11.000 --- --- 0.4331
--- 11.112 28/64   7/16 0.4375
--- 11.500 --- --- 0.4528
--- 11.509 29/64 --- 0.4531
--- 11.906 30/64 15/32 0.4688
--- 12.000 --- --- 0.4724
--- 12.200 --- --- 0.4803
--- 12.303 31/64 --- 0.4844
--- 12.500 --- --- 0.4921
--- 12.700 32/64   1/2  0.5000
--- 12.800 --- --- 0.5039
--- 13.000 --- --- 0.5118
--- 13.097 33/64 --- 0.5156
--- 13.494 34/64 17/32 0.5312
--- 13.500 --- --- 0.5315
--- 13.891 35/64 --- 0.5469
--- 14.000 --- --- 0.5512
--- 14.288 36/64   9/16 0.5625
--- 14.500 --- --- 0.5709
--- 14.684 37/64 --- 0.5781
--- 15.000 --- --- 0.5906
--- 15.081 38/64 19/32 0.5938
--- 15.478 39/64 --- 0.6094
--- 15.500 --- --- 0.6102
--- 15.875 40/64   5/8  0.6250
--- 16.000 --- --- 0.6299
--- 16.272 41/64 --- 0.6406
--- 16.500 --- --- 0.6496
--- 16.669 42/64 21/32 0.6563
--- 17.000 --- --- 0.6693
--- 17.066 43/64 --- 0.6719
--- 17.462 44/64 11/16 0.6875
--- 17.500 --- --- 0.6890
--- 17.859 45/64 --- 0.7031
--- 18.000 --- --- 0.7087
--- 18.256 46/64 23/32 0.7188
--- 18.500 --- --- 0.7283
--- 18.653 47/64 --- 0.7344
--- 19.000 --- --- 0.7480
--- 19.050 48/64   3/4  0.7500
--- 19.447 49/64 --- 0.7656
--- 19.500 --- --- 0.7677
--- 19.844 50/64 25/32 0.7813
--- 20.000 --- --- 0.7874
--- 20.241  51/64 --- 0.7969
--- 20.500 --- --- 0.8071
--- 20.638 52/64 13/16 0.8125
--- 21.000 --- --- 0.8268
--- 21.034 53/64 --- 0.8281
--- 21.431 54/64 27/32 0.8438
--- 21.500 --- --- 0.8465
--- 21.828 55/64 --- 0.8594
--- 22.000 --- --- 0.8661
--- 22.225 56/64   7/8  0.8750
--- 22.500 --- --- 0.8858
--- 22.622 57/64 --- 0.8906
--- 23.000 --- --- 0.9055
--- 23.019 58/64 29/32 0.9062
--- 23.416 59/64 --- 0.9219
--- 23.500 --- --- 0.9252
--- 23.812 60/64 15/16 0.9375
--- 24.000 --- --- 0.9449
--- 24.209 61/64 --- 0.9531
--- 24.500 --- --- 0.9646
--- 24.606 62/64 31/32 0.9688
--- 25.000 --- --- 0.9843
--- 25.003 63/64 --- 0.9844
--- 25.400 64/64 1       1.0000

Table values compiled from: 

Notes: 

  • Not all metric drill bits have imperial equivalents, and vice versa. 
  • Some metric values are close enough to essentially have the same imperial counterpart. 
  • Some values are rounded to their nearest thousandth millimeters and ten-thousandth decimal inches.

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