Ratio Calculator
Enter the two parts of a ratio to simplify it to its lowest terms and see it as a decimal. Add a third number to scale the ratio and solve for the missing value.
Simplifying a ratio
A ratio compares two quantities, such as 16:9 for a screen or 2:1 for a mix. To simplify it, divide both parts by their greatest common divisor — for example, 1920:1080 simplifies to 16:9.
Expressing the ratio as a single decimal (the first part divided by the second) makes it easy to compare two ratios at a glance.
Scaling to an equivalent ratio
Equivalent ratios keep the same proportion. If a recipe is 2:3 and you triple the first ingredient to 6, the second must scale to 9 to stay in proportion. Enter the new value for the first part and the calculator solves for the matching second part.
This is the same maths behind mixing ratios, map scales, aspect ratios and converting recipe quantities.
Frequently asked questions
How do I simplify a ratio?
Divide both numbers by their greatest common divisor. For example, 16:12 becomes 4:3. The calculator does this automatically.
How do I scale a ratio?
Enter the new value for the first part in the 'scale A to' box, and the calculator solves for the second part that keeps the ratio equivalent.