Ratio Calculator: Simplify, Scale and Share in a Ratio
Choose whether to simplify a ratio, find a missing value in a proportion, or divide a total between two parts. The answer updates as you type.
Estimates only. Check important results before you rely on them.
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From related categoriesHow to use this calculator
- Pick Simplify, Find X or Split a total.
- Enter A and B. These are the two parts of the ratio.
- For Find X enter C. For Split enter the total.
- Read the simplified ratio or the shares.
The formula
Worked example
24 : 36 simplifies to 2 : 3. If 24 : 36 = 9 : X, then X = 36 × 9 ÷ 24 = 13.5. Splitting 500 in the ratio 24 : 36 gives 200 and 300.
Understanding your result
Decimal ratios are scaled to whole numbers before simplifying, so 1.5 : 2.5 becomes 3 : 5. The percentage line shows what share of the whole each part is.
When to use it
- Mix paint, concrete or fertiliser in the right proportions.
- Share profit or cost between partners.
- Scale recipes, maps and drawings.
Assumptions and limits
This tool works with two-part ratios. A and B must be above zero. Results show up to four decimal places.
Frequently asked questions
What is a ratio?
A comparison of two quantities, written as A : B. A ratio of 2 : 3 means 2 parts for every 3 parts.
How do I simplify a ratio?
Divide both numbers by their greatest common divisor. 24 : 36 divided by 12 gives 2 : 3.
How do I solve a proportion?
Cross-multiply. In A : B = C : X, X equals B × C ÷ A.
How do I split an amount in a ratio?
Add the parts, divide the total by that sum, and multiply by each part.
Does the order matter?
Yes. 2 : 3 is not the same as 3 : 2. Keep A and B in the order you need.