Flag Calculator (US)
Calculate US flag dimensions from any single measurement using official Title 4 proportions. Get height, width, union size, star diameter, and stripe width.
About This Calculator
The Flag Dimensions Calculator (US) computes all official American flag proportions defined in Title 4 of the United States Code. Whether you need the height, width, union (canton) size, star diameter, stripe width, or star gap spacing, enter any single measurement and get the complete set of dimensions instantly.
The US flag proportions follow strict ratios established by law. The flag's height-to-width ratio is 10:19, meaning the width is always 1.9 times the height. The blue union (canton) in the top left corner spans 7 stripes in height (7/13 of the flag height) and extends 2/5 of the flag width. Each of the 13 alternating red and white stripes has equal width at 1/13 of the flag height. The 50 white stars are arranged in 9 alternating rows of 6 and 5 stars, with precise spacing defined as 1/10 of the union height vertically and 1/12 of the union width horizontally. Each star's diameter equals 4/5 of a single stripe width.
This calculator is ideal for DIY flag projects, woodworking, painting, digital design, educational demonstrations, and anyone needing precise American flag measurements. Enter the height or width in any unit (inches, feet, centimeters, meters) and all other dimensions are returned in the same unit.
Regional Notes
US: These dimensions follow US federal law (Title 4, Sections 1 and 2). Standard US flag sizes for residential use are 3×5 ft. Government buildings typically fly flags sized proportionally to the building.
IN / UK: This calculator is specific to the US flag proportions. India's national flag uses a different 2:3 aspect ratio, and the United Kingdom's Union Jack has its own unique proportions defined by the College of Arms.
Frequently Asked Questions
What are the official US flag proportions?
The official US flag proportions are defined in Title 4 of the United States Code. The flag height to width ratio is 10:19. The union (canton) height is 7/13 of the flag height, and the union width is 2/5 of the flag width. Each stripe is 1/13 of the flag height, and the star diameter is 4/5 of a stripe width.
How do you calculate US flag dimensions?
Enter either the flag height or width. The calculator applies the Title 4 ratios: Width = 1.9 × Height, Union Height = 7/13 × Height, Union Width = 0.76 × Width, Star Gap Vertical = 1/10 × Union Height, Star Gap Horizontal = 1/12 × Union Width, Star Diameter = 4/5 × Stripe Width, Stripe Width = 1/13 × Height.
What is the aspect ratio of the American flag?
The aspect ratio of the American flag is 10:19 (height to width). This means for every 10 units of height, the flag is 19 units wide.
What are standard US flag sizes?
Common US flag sizes include 3×5 ft (the most popular home size), 4×6 ft, 5×8 ft, and 6×10 ft for larger displays. Casket (burial) flags are typically 5×9.5 ft.
What are the official US flag colors?
The official US flag colors are: Old Glory Red (#B22234), White (#FFFFFF), and Old Glory Blue (#3C3B6E). These hex values are specified for accurate color reproduction of the American flag.
How many stars and stripes does the US flag have?
The US flag has 13 horizontal stripes alternating red and white, representing the original 13 colonies. It has 50 white stars on a blue canton, each representing one of the 50 US states, arranged in alternating rows of 6 and 5 stars.
When was the current US flag design adopted?
The current 50-star US flag was adopted on July 4, 1960, after Hawaii became the 50th state. The flag has had 27 official designs since 1777, with stars added as new states joined the Union.
Can I use any unit of measurement?
Yes. Enter the height or width in any unit (inches, feet, centimeters, meters). All computed dimensions will be returned in the same unit.