Flag Calculator

US Flag Official Proportions

The American flag follows fixed ratios defined in Title 4 of the United States Code. Every element scales from a single coefficient: flag height is 1.0, width is 1.9, the union spans seven stripes tall, and each stripe is one-thirteenth of the hoist. Knowing one measurement lets you derive all others for sewing, woodworking, or display projects.

Flag Dimension Ratios

Multiply each ratio by coefficient \(x\) (flag height in your chosen unit):

• Flag height (A) = \(1.0x\)
• Flag width (B) = \(1.9x\)
• Union height (C) = \(0.5385x\) (7/13 of height)
• Union width (D) = \(0.76x\) (2/5 of width)
• Stripe width (H) = \(0.0769x\) (1/13 of height)
• Star diameter (G) = \(0.0616x\)

The official aspect ratio is 10:19 (height to width).