Ratio Calculator

Simplify ratios, convert them to decimals, and solve for a missing value.

Simplified ratio

1:2


As a decimal

0.5

Solved (X)

0

A ratio compares two quantities by division. This calculator simplifies ratios by dividing both numbers by their greatest common divisor (GCD), converts the ratio to a decimal, and solves proportions like A:B = C:X to find the missing value X. Leave the C field at 0 to just simplify and convert a ratio.

simplify by GCD; solve A:B = C:X → X = B·C ÷ A

Examples

Simplify 4:8 by dividing both by their GCD of 4 to get 1:2, which equals 0.5 as a decimal.

Solve the proportion 3:4 = 9:X by calculating X = (4 × 9) ÷ 3 = 12.

FAQ

How do I simplify a ratio?

Find the greatest common divisor (GCD) of both numbers, then divide each by it. For example, 4:8 simplified is 1:2 because both 4 and 8 are divisible by 4.

How do I solve a proportion for x?

In a proportion A:B = C:X, cross-multiply to get A·X = B·C, then solve for X: X = (B·C) ÷ A.

What is a ratio as a decimal?

Divide the first number (A) by the second number (B). For the ratio 1:2, the decimal is 1 ÷ 2 = 0.5.