The maximum size flag on a flagpole varies depending on what material is used to construct the flagpole. Quinn Flags sells aluminum and fiberglass flagpoles.
Aluminum flagpoles:
Fiberglass flagpoles
Pole Height Above Ground (in ft)
Maximum Flag Size (in ft)
15 (Colonial only)
2x3
20
3x5
20 (Colonial only)
25
4x6
30
5x8
35
6x10
40
8x12
39
50
10x15
60
12x18
70
15x25