Calculators
Ratio Calculator
Solve equivalent ratios such as 2:3 = x:12, find any missing value, and see the simplified form of a ratio.
Good to know
Frequently asked questions
How do I find a missing value?
Type the three values you know and leave the fourth box empty. The answer is calculated from the cross products as soon as you finish typing.
Can I use decimals?
Yes. Decimal values are supported, and the simplified ratio is shown where a sensible whole-number form exists.
What is the scale factor?
It is how many times bigger the second ratio is than the first — useful when scaling recipes, drawings or image sizes.
Why do I get a divide-by-zero message?
Some value combinations make the proportion impossible to solve, such as a zero in the position the formula divides by. Adjust one value to continue.