Boat Flag Sizes

An Official Guide to Boating Flags

Powerboat Length Flag Size Sailboat Length Flag Size
up to 18'10x15" flag up to 30'10x15" flag
19' to 24'10x15" flag 31' to 36'12x18" flag
25' to 30'12x18" flag 37' to 48'16x24" flag
31' to 36'16x24" flag 49' to 60'20x30" flag
37' to 48'20x30" flag 61' to 72'24x36" flag
49' to 60'24x36" flag   
61' to 72'30x48" flag   

U.S. Ensign

Powerboat or
Sailboat Length
Flag Size
up to 18'12x18" flag
19' to 24'16x24" flag
25' to 30'20x30" flag
31' to 36'24x36" flag
37' to 48'30x48" flag
49' to 60'3x5 ft flag
61' to 72'4x6 ft flag