Letter Drill Sizes

This chart shows the diameters of letter gauge drills size A (the smallest) to size Z (the largest).

Drill	Inch	mm
A	0.234	5.94
B	0.238	6.05
C	0.242	6.15
D	0.246	6.25
E	0.250	6.35
F	0.257	6.53
G	0.261	6.63
H	0.266	6.76
I	0.272	6.91
J	0.277	7.04
K	0.281	7.14
L	0.29	7.37
M	0.295	7.49
N	0.302	7.67
O	0.316	8.03
P	0.323	8.20
Q	0.332	8.43
R	0.339	8.61
S	0.348	8.84
T	0.358	9.09
U	0.368	9.35
V	0.377	9.58
W	0.386	9.80
X	0.397	10.08
Y	0.404	10.26
Z	0.413	10.49

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