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Flag Dimensions Calculator (US proportions)

Works out flag dimensions and the official US flag proportions. Enter the hoist or fly with a chosen aspect ratio and it returns the canton size, stripe width, and star diameter per 4 USC section 1.

How to use
  1. Choose an aspect ratio such as 10:19 government or 2:3 residential.
  2. Enter the hoist or the fly length.
Hoist
Flag size (hoist × fly)
36 × 68.4 in

10 : 19 (hoist : fly)

Estimates for general information, verify important figures before relying on them.
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How it's calculated

fly = hoist × (b ÷ a), area = hoist × fly

hoist = flag height (A), fly = flag length, a:b = official ratio (10:19 for US Government). Union height = 7/13 A, union width = 0.76 A, stripe width = 1/13 A, star diameter = 4/5 stripe.

Common questions

What is the official US flag aspect ratio?

The government standard is 10:19, hoist to fly, though residential flags often use a 2:3 ratio.

How wide is each stripe on a US flag?

Each of the 13 stripes is one thirteenth of the flag's hoist height.

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