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Flag Ratio Calculator
Enter a flag’s aspect ratio (width to height) and one known dimension to calculate the matching dimension and total flag area.
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What this calculator does
Flags are made to a standard width-to-height aspect ratio (for example, 3:5). This calculator finds the missing dimension of a flag once you know its ratio and either its width or its height, and also reports the total fabric area.
How the calculation works
If you know the width, height = width × (ratio height ÷ ratio width). If you know the height, width = height × (ratio width ÷ ratio height). Area is simply width multiplied by height.
Common flag ratios include 3:5, 2:3, and 1:2, but they vary by country and manufacturer, so confirm the specific ratio you need before ordering fabric.
Last reviewed August 2026