What size flag do I require?
The size of a flag is measured by its length or fly, and this is governed in yards.
The shorter breadth is known as the hoist.
Approximate size is determined by the height at which the flag is flown. The simple rule to determine this is 1 yard for every 10' of flagstaff. Therefore, a 25', free standing, flagpole would require a 2.5 yard flag and 40' flagpole would require a 4 yard flag.
Different considerations apply when the flag is flying from a flagstaff on the top of a building. Here size is based on the overall proportions of the flag. In order to ensure that the flag appears aesthetically correct when flying, one should generally adaopt a scale of 1sq. ft. of flag per 1 linear foot of height.
Please remember, this is a general rule and may not apply in all situations.