Math
Ratio Calculator
Simplify ratios, scale them up or down, and find missing values in proportions.
Ratio A : B
Simplified Ratio
3 : 5
Scaled Ratio (×2)
6 : 10
Frequently asked questions
What is a ratio?
A ratio shows the relative sizes of two or more values. A ratio of 3:5 means for every 3 of the first thing, there are 5 of the second.
How do you simplify a ratio?
Divide both numbers by their greatest common divisor (GCD). For example, 6:10 simplifies to 3:5 because both share a GCD of 2.
What does 'find missing C' mean?
If you know A:B = C:D and three of the four values, we use cross-multiplication (A×D = B×C) to calculate the missing one.
Can ratios have decimals?
Yes, ratios can contain decimal numbers. They will still be simplified as much as possible, though decimals may remain.
Simplify ratios, scale them up or down by a factor, and find missing values in proportions (A:B = C:D). Perfect for recipe scaling, map distances, and mixing ratios.