Ratio Calculator
Simplify ratios and solve proportions instantly — runs entirely in your browser.
Simplifying ratios and solving proportions
A ratio compares two quantities. To simplify a ratio, the tool divides both terms by their greatest common divisor (GCD), reducing them to the smallest whole numbers that preserve the relationship. For example, 6:4 simplifies to 3:2 because the GCD of 6 and 4 is 2. To solve a proportion, enter three of the four values in A:B = C:x and the missing term x is calculated as (B times C) divided by A.
Ratios are used everywhere from scaling recipes to map distances to mixing paint. The calculator handles both integer and decimal inputs and runs entirely in your browser.
FAQ
What is GCD? The greatest common divisor of two numbers is the largest integer that divides both without a remainder. Dividing both ratio terms by their GCD gives the simplest equivalent ratio.
What is a proportion? A proportion states that two ratios are equal: A:B = C:x. Cross-multiplying gives A times x = B times C, so x = (B times C) / A.
Can I use decimal values? Yes. The simplify mode uses rounding to integers before applying GCD, so it works best with whole numbers. The proportion solver handles decimals precisely.