Ratio calculator
Solve a proportion, simplify a ratio, or share out an amount in a ratio.
Questions people ask
How do I solve a proportion?
Cross-multiply: if A : B = C : D, then D = B × C ÷ A. For 3 : 4 = 9 : ?, the answer is 4 × 9 ÷ 3 = 12.
How do I split an amount in a ratio?
Add the parts, divide the total by that sum to get one part, then multiply. 120 in the ratio 2 : 3 is 120 ÷ 5 = 24 per part, so 48 and 72.