Ratio Calculator
Simplify ratios or solve a:b = c:d for the missing value.
Last updated: August 2026
Simplified ratio
2 : 3
Original 6 : 9
Percentage split
40% / 60%
Share of first term / second term
Simplifying divides both terms by their greatest common factor, so 6:9 becomes 2:3.
How it works
Simplify: divide both parts by GCD. Solve a:b = c:d → d = (c × b) ÷ a.
Example: 6:9 → 2:3. If 2:3 = 4:d, then d = 6.
Frequently Asked Questions
How do I simplify a ratio?
Divide both parts by their greatest common factor. The ratio 6:9 simplifies to 2:3 because both divide by 3.
How do I solve a:b = c:d for the missing value?
Cross-multiply: d = (c × b) ÷ a. If 2:3 = 4:d, then d = (4 × 3) ÷ 2 = 6.
What does a ratio mean in everyday life?
A ratio compares quantities, like mixing paint 2:1 (two parts paint, one part thinner) or diluting juice concentrate 1:4.
How is a ratio different from a fraction?
A ratio compares two quantities (2:3), while a fraction is a single number. A ratio can be written as a fraction — in 2:3, the first part is 2/5 of the whole.