Maths Proportion

Ratio calculator

Mode
First number
Second number
Simplified ratio 3 : 4
6 : 8 reduced by their common factor
As a decimal 0.75
First as a share 42.857 %
Reversed 4 : 3
Per one 1 : 1.3333
Reduced by the greatest common divisor

A ratio of 1.5 : 2 is not stuck as a decimal — scaling both sides by ten gives 15 : 20, which reduces to 3 : 4. This tool does that automatically by working in whole numbers behind the scenes, which is why entering measured values with decimal places still produces a clean ratio rather than an unhelpful 0.75 : 1.

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A ratio simplifies by dividing both sides by their greatest common divisor: 6 : 8 becomes 3 : 4. To solve a proportion A : B = C : x, multiply B by C and divide by A. To split by shares, divide the total by the sum of the parts.

How to work with ratios

1 Choose whether you are simplifying, solving a proportion, or splitting an amount.
2 Enter the numbers — decimals are handled and still reduce cleanly.
3 Read the simplified form, the decimal and the percentage together.
4 For a split, enter one share per line.

The three modes cover almost everything ratios are used for. Simplifying puts a measured relationship into its clearest form. Solving a proportion is the scaling operation behind recipes, map scales, mixing paint and converting units. Splitting by shares is how profit, rent and inheritance get divided — and it is the one where the arithmetic most often goes wrong, because people divide by the number of shares rather than by their sum.

Questions

Divide both sides by their greatest common divisor. 6 : 8 divided by 2 is 3 : 4.

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