Ratio to Percentage Calculator

Understanding ratios is easier when they are converted into familiar percentages. This calculator takes a standard A:B ratio, simplifies it to its lowest terms using the greatest common divisor, calculates the exact decimal form, and outputs the equivalent percentage. It is useful any time you need to quickly express a ratio as a proportion — for test scores, financial comparisons, ingredient quantities, pass rates, manufacturing defect ratios, survey response rates, or any situation where you know two related quantities and want to express them as a clean, easy-to-communicate percentage. The simplified ratio is also shown alongside the percentage so you get both the reduced form and the percentage equivalent without doing any separate calculations. Results are shown to four decimal places for precision. A ratio where A is larger than B produces a percentage above 100%, which is mathematically valid and commonly seen when comparing revenue to cost, actual to budget, or output to target. This calculator handles all such cases correctly without any manual adjustment.

The calculator treats the ratio A:B as the fraction A ÷ B. The first number (A) is divided by the second number (B) to produce the decimal representation. That decimal is then multiplied by 100 to produce the percentage. In parallel, the greatest common divisor (GCD) of A and B is found using the Euclidean algorithm — repeatedly taking the remainder of dividing the two values until zero — and both numbers are then divided by the GCD to display the simplified ratio. This gives you three equivalent representations of the same relationship in a single calculation: a simplified ratio in lowest terms, its exact decimal form, and the corresponding percentage. A percentage above 100% simply means A is larger than B, which is mathematically valid and common when comparing growth, performance, or any quantity where the part exceeds the whole.