Ratio calculator

Compare quantities by simplifying their ratio, or find a missing value when scaling a recipe or drawing. These two modes keep the relationship between the quantities visible: a reduced pair of integers, or the unknown X in a proportion.

MAKE IT SIMPLE

Result

Worked examples

12 : 18

2 : 3

Both values divide by their greatest common divisor, 6.

2 : 3 = 10 : X

X = 15

Scaling the first quantity by five also scales the second quantity by five.

Questions & answers

Can either side of a simplified ratio be zero?

Yes. 0 : 8 simplifies to 0 : 1, while 8 : 0 simplifies to 1 : 0. A pair of zeros has no unique reduced ratio and is rejected.

How is this different from a percentage?

A ratio compares two quantities as a pair. A percentage expresses a quantity relative to a base of 100. Use the percentage calculator when you need a percent result.

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