Ratio Calculator
Simplify ratios, solve proportions & scale ratios — with step-by-step solutions.
About this calculator
Simplify mode reduces a ratio to its simplest form by dividing both parts by their GCD. Proportion mode solves a:b = c:x for the missing value x using cross-multiplication. Scale mode multiplies both parts of a ratio by a factor. Handles integers and decimals.
How ratios and proportions work
A ratio compares two quantities. Simplifying a ratio means dividing both parts by their Greatest Common Divisor (GCD). A proportion states that two ratios are equal (a:b = c:d). To solve for a missing value, cross-multiply: a × d = b × c. Ratios are used throughout mathematics, cooking, construction, finance, and science.