Hoist (width) of flag (A) 1.0
Fly (length) of flag (B) 1.9
Hoist (width) of Union (C) 0.5385 (7/13)
Fly (length) of Union (D) 0.76
Diameter of star (K) 0.0616
Width of stripe (L) 0.0769 ( 1/13)
The official regulation at the Defense Technology Information Center website
http://www.dtic.mil is General Services Administration
"Federal Specification, Flag, National, United States of
America and Flag, Union Jack," DDD-F-416E, dated November 27, 1981.
It specifies the colors by reference to "Standard Color Cards of America" maintained
by the Color Association of the United States, Inc. These are:
Cable No. 70180 Old Glory Red
Cable No. 70001 White
Cable No. 70075 Old Glory Blue
In the Pantone system the colors are: Blue PMS 282 and Red PMS 193.
View the Government drawing (45k gif 1493 pixels w x 879 pixels h) specifying the Flags dimensions.