Ratio Calculator

Solve proportions (A:B = C:X) and simplify ratios — for recipes, scale models, maps and mixing. Runs in your browser.

Runs in your browser — your file never leaves your device

Frequently asked questions

Is Ratio Calculator free to use?

Yes — Ratio Calculator is completely free with no limits, no watermarks and no sign-up. It runs in your browser, so there is nothing to pay for.

Are my files uploaded or stored anywhere?

No. This tool does all its work locally in your browser using your own device's power. Your files never leave your device and we never see them.

Do I need to install anything or create an account?

No installation and no account needed. Ratio Calculator works on any modern browser — Windows, Mac, Linux, Android and iPhone.

How do I use Ratio Calculator?

Open the tool, add your file (or paste your content), adjust any options, then press “Solve ratio”. Your result is ready to download in seconds.

Slope, line equation, distance, midpoint.

Averages where some values count more.

Decimals, significant figures, or nearest N.

0.00034 ↔ 3.4 × 10⁻⁴.

Append blank pages to a PDF.

Draw your signature and place it on the page.