Ratio & Proportion Calculator

Simplify ratios, scale up/down, and solve proportions like a:b = c:x. Auto-saves your inputs in the URL.

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Simplify ratio
Scale ratio
Solve proportion
Simplifies A:B by dividing by the greatest common divisor (for integers) or by reducing proportionally.
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Explanation

Works with ratios in 3 modes: simplify, scale, and solve for x.

  • Simplify: divide both sides by their GCD (greatest common divisor).
  • Scale: multiply both sides by the same factor to resize the ratio.
  • Solve: for a:b = c:x → x = (b×c) ÷ a.