Ratio & Proportion Calculator
Simplify ratios like 12:18 to 2:3, scale a ratio to a total, and solve proportions (a:b = c:x) for the missing value.
How to use
- 1Choose simplify, solve or split a total.
- 2Enter the numbers.
How it's calculated
Simplify: divide both parts by their GCF. Solve a:b = c:x → x = b × c ÷ a. Split total T in ratio a:b → T × a ÷ (a + b) and T × b ÷ (a + b).
Frequently asked questions
How do I simplify a ratio with decimals?
Multiply both parts by 10, 100 … until they're whole numbers, then divide by the GCF: 1.5:2.5 = 15:25 = 3:5.
How do I split money in a ratio?
Add the parts, divide the total by that sum, then multiply by each part: $120 in 1:2 = $40 and $80.
What's the difference between ratio and proportion?
A ratio compares two quantities; a proportion states two ratios are equal.