Everyday Maths

Ratio Calculator

Simplify ratios, scale a ratio up or split a total into parts. Useful for recipes, comparisons, mixtures and quick everyday maths.

Calculate a ratio

Enter two or three parts. You can simplify the ratio, scale it by a multiplier, or split a total amount according to the ratio.

Example: flour, person A, blue paint.
Example: water, person B, white paint.
Use for three-part ratios such as 3:2:1.
Split this total using the ratio.
Multiply every part by this number.
Controls rounded scaled results.
Simplified ratio

Smallest whole-number version.

Total parts

Add all simplified ratio parts.

Scaled to total

Each part's share of your total.

Scaled by multiplier

Every part multiplied equally.

Value per part

Total divided by total parts.

Plain-English result

A quick interpretation.

How the ratio calculator works

A ratio compares amounts in parts. If a recipe uses flour and water in a ratio of 2:3, that means for every 2 parts of flour you use 3 parts of water.

Simplify ratio = divide each part by the greatest common divisor Scale to total = total ÷ total ratio parts Each share = ratio part × value per part

A proportion keeps the same relationship while the numbers get larger or smaller.

Ratio examples

ExampleCalculationResult
Simplify 10:20Divide both sides by 101:2
Split 100 in the ratio 2:3Total parts = 5, each part = 2040:60
Scale 3:2:1 to total 60Total parts = 6, each part = 1030:20:10

When ratios are useful

  • Recipes: scale ingredients without changing the balance.
  • Shopping: compare quantities alongside the unit price comparison calculator.
  • Percentages: convert part-to-whole relationships with the percentage calculator.
  • Splitting totals: divide money, time or quantities into fair shares.

Ratio calculator FAQs

How do you simplify a ratio?

Divide every part of the ratio by the largest number that divides evenly into all parts. For example, 10:20 simplifies to 1:2.

How do you split a total into a ratio?

Add the ratio parts together, divide the total by that number, then multiply each ratio part by the value per part.

Can a ratio have three parts?

Yes. Ratios such as 3:2:1 are common in recipes, mixtures and comparisons. The calculator supports two-part and three-part ratios.