Num.
&
Letter
Drills
Fract.
Drills
Decimal
Equiv.
80 ... .0135
79 ... .0145
  1/64 .0156
78 ... .0160
77 ... .0180
76 ... .0200
75 ... .0210
74 ... .0225
73 ... .0240
72 ... .0250
71 ... .0260
70 ... .0280
69 ... .0292
68 ... .0310
  1/32 .0312
67 ... .0320
66 ... .0330
65 ... .0350
64 ... .0360
63 ... .0370
62 ... .0380
61 ... .0390
60 ... .0400
59 ... .0410
58 ... .0420
57 ... .0430
56 ... .0465
  3/64 .0469
55 ... .0520
54 ... .0550
53 ... .0595
  1/16 .0625
52 ... .0635
51 ... .0670
50 ... .0700
49 ... .0730
48 ... .0760
  5/64 .0781
47 ... .0785
46 ... .0810
45 ... .0820
44 ... .0860
43 ... .0890
42 ... .0935
  3/32 .0937
41 ... .0960
40 ... .0980
39 ... .0995
38 ... .1015
37 ... .1040
36 ... .1065
  7/64 .1094
35 ... .1100
34 ... .1110
33 ... .1130
32 ... .1160
Num.
&
Letter
Drills
Fract.
Drills
Decimal
Equiv.
31 ... .1200
  1/8 .1250
30 ... .1285
29 ... .1360
28 ... .1405
  9/64 .1406
27 ... .1440
26 ... .1470
25 ... .1495
24 ... .1520
23 ... .1540
  5/32 .1562
22 ... .1570
21 ... .1590
20 ... .1610
19 ... .1660
18 ... .1695
  11/64 .1719
17 ... .1720
16 ... .1770
15 ... .1800
14 ... .1820
13 ... .1850
  3/16 .1875
12 ... .1890
11 ... .1910
10 ... .1935
9 ... .1960
8 ... .1990
7 ... .2010
  13/64 .2031
6 ... .2040
5 ... .2055
4 ... .2090
3 ... .2130
  7/32 .2187
2 ... .2210
1 ... .2280
A ... .2340
  15/64 .2344
B ... .2380
C ... .2420
D ... .2460
E 1/4 .2500
F ... .2570
G ... .2610
  17/64 .2656
H ... .2660
I ... .2720
J ... .2770
K ... .2810
  9/32 .2812
L ... .2900
M ... .2950
  19/64 .2969
N ... .3020
Num.
&
Letter
Drills
Fract.
Drills
Decimal
Equiv.
  5/16 .3125
O ... .3160
P ... .3230
  21/64 .3281
Q ... .3320
R ... .3390
  11/32 .3437
S ... .3480
T ... .3580
  23/64 .3594
U ... .3680
  3/8 .3750
V ... .3770
W ... .3860
  25/64 .3906
X ... .3970
Y ... .4040
  13/32 .4062
Z ... .4130
  27/64 .4219
  7/16 .4375
  29/64 .4531
  15/32 .4687
  31/64 .4844
  1/2 .5000
  33/64 .5156
  17/32 .5312
  35/64 .5469
  9/16 .5625
  37/64 .5781
  19/32 .5937
  39/64 .6094
  5/8 .6250
  41/64 .6406
  21/32 .6562
  43/64 .6719
  11/16 .6875
  45/64 .7031
  23/32 .7187
  47/64 .7344
  3/4 .7500
  49/64 .7656
  25/32 .7812
  51/64 .7969
  13/16 .8125
  53/64 .8281
  27/32 .8437
  55/64 .8594
  7/8 .8750
  57/64 .8906
  29/32 .9062
  59/64 .9219
  15/16 .9375
  61/64 .9531
  31/32 .9687
  63/64 .9844
  1 1.0000
Source: Drill Bit Sizes at OffRoaders.com/info/tech-corner

last updated 1 Apr 2005