A ratio expresses how one quantity relates to another. 2:3 means two of one for every three of another. Ratios can be scaled (multiply both sides by the same factor) without changing their meaning.

How do I solve a proportion?

For A:B = C:D, cross-multiply: A·D = B·C. Solve for the unknown. Example: 2:3 = x:12 → 2·12 = 3·x → x = 8.

How is a ratio simplified?

Divide both parts by their greatest common divisor (GCD). Example: 24:36 — GCD(24, 36) = 12, so simplified = 2:3. For decimals, multiply both sides by 10^n until both are whole.

Ratio vs. fraction vs. percentage?

Ratio 2:3 = fraction 2/3 ≈ 0.667 = 66.67%. Note: 2:3 and 2/5 are different — the ratio 2:3 has a total of 5 parts, so 2/5 is the share.

Ratio Calculator

Calculators· 14 tools

Free ratio calculator. Solve A:B = C:D for any unknown, simplify any ratio to its lowest terms using GCD, scale ratios up or down, and convert between ratios, fractions, decimals, and percentages. Works with whole numbers and decimals.

Mode

Unknown value

Uses cross-multiplication for solving, GCD for simplification.

C =

2 : 3 = 8 : 12

A / B (decimal)0.6667

A / B (percentage)66.67%

A share of total40.00%

Frequently Asked Questions

References

Ratio — Weisstein, Eric W. MathWorld — Wolfram MathWorld

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Frequently Asked Questions

References and sources

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