Ratio Calculators
Simplify a ratio to its lowest terms and see it as a share of the whole.
A ratio compares two or more quantities, such as 2 parts concentrate to 3 parts water. A proportion states that two ratios are equal, which is how recipes, map scales and mixtures are scaled up or down.
Use these calculators to reduce a ratio to its simplest whole-number form, see each part as a share of the whole, or find the missing value that keeps two ratios equal.
Calculators in this category
Which calculator do I need?
- What is 12 : 18 in its simplest form? The Ratio Calculator simplifies a two-part ratio, including decimal ratios, and shows each side as a percentage of the total.
- A recipe for 4 needs 300 g of flour. How much for 6? The Proportion Calculator solves a : b = c : x by cross-multiplication.
Good to know
Order matters in a ratio: 2 : 3 and 3 : 2 describe different mixtures.
To share an amount in a ratio with three or more parts, add the parts, divide the amount by that total, and multiply each part by the result: 85 in the ratio 12 : 2 : 3 is 17 parts of 5, so the shares are 60, 10 and 15. The ratios and proportions guide works through this and map scales.
Background reading
- Ratios and proportions What a ratio says, how to simplify one, how to share an amount in a ratio, and how to solve proportions for recipes, maps and mixtures.