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Ratio Calculator
Calculate ratios, proportions, and parts of a whole just by entering the numbers. Supports A:B ratios, percentage conversion, and integer-ratio suggestions such as 16:9. Free and no sign-up required.
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How to Use
2-Term Ratio Tab
Enter the base ratio on the left (e.g., 16 and 9), then enter one known value on the right (e.g., 1920) to automatically calculate the other value (e.g., 1080).
Use the ⇄ button to swap the input and output sides for reverse calculation.
Multi-Term Ratio Tab
Calculate ratios with three or more terms. Enter the ratio for each row, then input a base value in any one row to automatically calculate the others. The blue-highlighted row is the base row.
Integer Ratio Suggestions
When the result is a decimal, the nearest integer ratio candidates appear automatically. Click a suggestion to apply it.
Presets
Quickly apply common ratios (16:9, Golden Ratio, A4, etc.) from the dropdown with a single click.
FAQ
What is a ratio?
A ratio expresses the relative sizes of two or more quantities in the form A:B. For example, 16:9 means a width of 16 for every height of 9. Once one value is known, the other follows from A:B = C:X.
How do I simplify a ratio?
Divide both values by their greatest common divisor to get the simplest integer ratio. Example: 1920:1080 divided by 120 becomes 16:9. This tool also suggests the nearest integer ratio when the result is a decimal.
What is the difference between a ratio and a percentage?
A ratio compares elements to each other (A:B), while a percentage expresses each part relative to the whole (out of 100%). Convert with “value / total x 100”, or use the percentage calculator.