Ratio Calculator
Simplify a ratio A:B to lowest terms, or solve a proportion A:B = C:x to find the missing value. Also converts the ratio to a decimal and a percentage.
Simplified ratio
16 : 9
As a decimal (A ÷ B)
1.777778
A as % of total
64%
A ratio is simplified by dividing both parts by their greatest common divisor. In a proportion, cross-multiply: A × x = B × C, so x = (B × C) ÷ A.
Frequently Asked Questions
How do I simplify a ratio?
Divide both numbers in the ratio by their greatest common divisor (GCD). For example, 16:8 has a GCD of 8, so it simplifies to 2:1. This calculator reduces any ratio to its lowest whole-number terms, and it handles decimals too.
How do I solve a proportion like A:B = C:x?
Cross-multiply. From A:B = C:x you get A × x = B × C, so x = (B × C) ÷ A. For example, 3:4 = 9:x gives x = (4 × 9) ÷ 3 = 12. Use the proportion mode above and the calculator solves for x automatically.
What is a ratio versus a fraction?
A ratio compares two quantities (A:B), while a fraction expresses a part of a whole (A/B). The ratio 3:4 means there are 3 parts of one thing for every 4 of another, which is the same numbers as the fraction 3/4 but a different interpretation.
Can I simplify a ratio with decimals?
Yes. Enter values like 1.5:3 and the calculator scales them to whole numbers before reducing, giving 1:2. It tracks the decimal places automatically so the simplified ratio is always in whole numbers.
How do I convert a ratio to a percentage?
Divide one part by the sum of both parts and multiply by 100. For the ratio 3:1, the first part is 3 ÷ (3 + 1) × 100 = 75% of the total. The calculator shows this for the A part automatically.