Flag Tips and Guides — flagpoles

For a 20-foot residential flagpole, the most common and well-proportioned flag size is 3' × 5'. Best overall: 3' × 5' More prominent display: 4' × 6' Heavy or windy location: 3' × 5' is usually the better choice because it puts less strain on the pole and hardware. Commercial or larger-diameter pole: A 4' × 6' may be appropriate. For most 20-foot flagpoles, I would recommend a 3' × 5' nylon flag.