Ratio Calculator
Simplify, compare, scale and find equivalent ratios. Useful for cooking, scaling recipes, comparing rates and proportions.
Solve: A : B = C : D
How to use the Ratio Calculator
- Enter your inputs into the Ratio Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The ratio operations
Simplify: divide both terms by GCD · · · Equivalent: multiply both terms by the same factor · · · Compare: cross-multiply
Ratios can be expressed in different forms: a:b, a/b, "a to b." Equivalent ratios represent the same proportion. Two ratios a:b and c:d are equal if ad = bc.
Worked example
Simplify 18:24: GCD is 6, so 18:24 = 3:4. Scale 2:5 to a total of 35: 2+5=7 parts, scale factor 5, so 10:25. Compare 3:4 and 9:12: 3×12 = 4×9 → equal.
Frequently asked questions
What's the difference between ratio and proportion?
A ratio is a comparison of two quantities (3:4). A proportion is an equation showing two ratios are equal (3:4 = 9:12).
How do I scale a recipe?
Use ratios. To double a recipe that calls for 2 cups flour, 1 cup sugar (ratio 2:1), keep the ratio and scale both ingredients — 4 cups flour, 2 cups sugar.
Can a ratio have more than two terms?
Yes — a ratio of 3 ingredients might be 2:3:5. The same simplification and scaling rules apply to all terms simultaneously.