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