Ratio Calculator — Solve Proportions Online

Calculate and solve ratios and proportions. Find missing values in A:B = C:D equations.

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Frequently Asked Questions

How do I use Ratio Calculator?
Enter any two values of a ratio and the tool simplifies it to its lowest terms and calculates the missing value if needed.
Is Ratio Calculator free?
Yes, Ratio Calculator on ToolPix is 100% free with no signup or installation required.
Is my data safe?
All processing happens in your browser, your data never leaves your device.
Can it solve proportions?
Yes — enter three of the four values in a proportion (A:B = C:D) to solve for the missing one.
What are ratios used for?
Ratios are used in recipe scaling, image aspect ratios, map scales, financial analysis, and many everyday calculations.