Flag Calculator - Executive Order 10834 Proportions

A flag calculator applies the official Executive Order 10834 proportions to one user-supplied measurement and returns the full set of dimensions for the American flag.

• • Sizing a wooden American flag project: Pick the board width as the reference, choose inches or centimeters, and read every other cut length in one pass.
• • Verifying a purchased flag meets the official proportions: Measure the flag you own, enter that measurement, and compare every named dimension on the result panel against your tape.
• • Planning a display case for a 3 ft by 5.70 ft home flag or 5 ft by 9.50 ft casket flag: Enter the typical 3 ft home hoist or the 5 ft casket hoist, and the calculator returns the union width, stripe height, and star diameter at the same time.
• • Teaching the Executive Order 10834 ratios in a classroom: Use the calculator to walk students through the eight official ratios, then show how swapping the reference dimension keeps the same flag layout.

The eight named dimensions - A through H - cover every element on the flag, so the result panel doubles as a measurement checklist for builders, etchers, quilters, and classrooms alike.

When the package has to fit a flag box of a known size, the dimensional weight calculator converts the same kind of length times width times height product into a billable weight for shipping.

The calculator treats every dimension as a multiple of a hidden scaling coefficient x, and recovers x by dividing the input by the matching Executive Order 10834 ratio.

• reference_dimension: Which of the eight named dimensions the user already knows (A through H). Determines the Executive Order 10834 ratio used to recover the proportion coefficient x.
• reference_value: The numerical measurement of the chosen reference dimension, in the selected display unit. Must be positive.
• unit: Display unit for the inputs and outputs. The calculator converts to meters internally so the math is unit-agnostic.
• proportion_coefficient (x): Hidden scaling factor derived by dividing the converted input value by its Executive Order 10834 ratio. Drives every other output.

According to Office of the Federal Register: Executive Order 10834, the flag dimensions are 1.0 hoist to 1.9 fly, a union hoist of 0.5385 (7/13) of the hoist, a union fly of 0.76 of the hoist, a stripe width of 0.0769 (1/13) of the hoist, and a star diameter of 0.0616 of the hoist.

For the underlying ratio math between A and B or between C and D, the ratio calculator shows how to reduce a pair like 10:19 to its simplest integer form and back.

Four small ideas explain why any one of the eight dimensions produces the same flag layout.

The Executive Order 10834 ratios define the shape, x scales it, the 10:19 ratio confirms the proportions, and the 5.385:7.6 ratio confirms the canton.

When a classroom needs the same x = V / r step spelled out as a proportion problem, the proportion calculator walks through the cross-multiplication that the flag calculator does internally.

Five short steps turn one known measurement into the full Executive Order 10834 layout.

1. 1 Pick the dimension you already know: Use the Reference Dimension dropdown to choose A through H. Most users start with A because it is the easiest tape reading, even though the 10:19 fly (5.70 ft for a 3 ft hoist) is wider than the 5 ft printed on commercial "3x5" flag packaging.
2. 2 Choose the display unit: Select inches, feet, centimeters, or meters. The calculator converts to meters internally so the math stays unit-agnostic.
3. 3 Enter the reference value: Type a positive number for the chosen reference dimension. The home flag is 3 ft tall; a casket flag is 5 ft tall.
4. 4 Read the eight derived dimensions: The result panel updates right away with the flag hoist, fly, union hoist, union fly, stripe width, star gap, and star diameter.
5. 5 Audit the proportion coefficient: Use the proportion coefficient x as a sanity check. Re-enter the calculation with a different reference dimension and confirm it matches.

If your flag has a 3 ft hoist, set Reference Dimension to A, Reference Value to 3, Unit to feet. The calculator returns a union fly D of 2.28 ft; tape the blue canton and you should land within a tenth of an inch of that. A commercial "3 ft by 5 ft" flag uses the looser 3:5 ratio, so its canton measures closer to 2 ft wide.

If you want to render the same proportions as a CSS aspect-ratio value for a hero image or a print mockup, the CSS aspect ratio calculator turns a width and a height into the matching aspect-ratio declaration.

A purpose-built flag calculator keeps all eight Executive Order 10834 dimensions in one place and lets you start from any of them.

• • Single-input flag sizing: Type any one named dimension and the calculator fills in the remaining seven, so you skip the math.
• • Built on the official Executive Order 10834 ratios: Every output uses the proportions from the order that has governed the 50-star flag since 1960, so the result panel is also a measurement checklist for builders, etchers, and quilters.
• • Works in inches, feet, centimeters, and meters: Pick the unit that matches your tape and the calculator converts internally, so the same flag appears whether you typed inches or meters.
• • Visible proportion coefficient x: The scaling coefficient is printed in the result panel, so you can re-enter the calculation with a different input to confirm it.
• • Sanity checks against the 10:19 and 5.385:7.6 ratios: The hoist-to-fly ratio A to B and the union aspect ratio C to D appear in the result panel, so a finished flag can be audited at a glance.

Switching from height to stripe width keeps the flag unchanged - the cleanest demonstration that Executive Order 10834 defines proportions, not absolute sizes.

For a board-and-batten American flag wall hanging, the board and batten calculator turns the strip widths and spacings from the flag calculator into the count and lengths of 1x4 boards to buy.

Three inputs shape every output, and three caveats describe where the Executive Order 10834 proportions stop being authoritative.

• • Executive Order 10834 only sets the proportions of the flag of the United States. Other national flags use different ratios (the Union Jack is 1:2, the French tricolor is 2:3), so this calculator only sizes the United States flag.
• • The calculator returns physical dimensions only. It does not check fabric weight, grommet placement, or pole length, which Title 4 USC addresses in 4 U.S.C. §§ 5-8.
• • Display rounding to 2 decimal places (4 for meters) is meant for builders, not legal inspection. The original Executive Order 10834 text is the source that counts.

The only thing that changes between a 3 ft home flag and a 30 ft display flag is the proportion coefficient x.

According to USA.gov: The U.S. Flag, the flag should not touch the ground, should not be displayed in bad weather unless it is an all-weather flag, and should be raised briskly and lowered ceremonially, so a flag sized here should also leave a small floor clearance.

For a wooden flag project, the board foot calculator turns the A through H dimensions into the board feet of pine or cedar you actually need at the lumber yard.