Proportion Calculator
Proportion Calculator exists to do one job well: solve a/b = c/x. Every figure is worked out on your own device using standard formulas — nothing you type is transmitted, which matters when the numbers are your salary, loan or health data. It is used most by anyone tracking a fitness or weight goal week to week. Uses double-precision arithmetic, accurate well beyond everyday needs. Free, unlimited, and free of the upsells most tools of this kind carry.
Key features
- Uses double-precision arithmetic, accurate well beyond everyday needs.
- Figures are indicative — they are not financial, medical or legal advice.
- Works on desktop, tablet and phone — no separate app to install.
- Loads in under a second and gives its result in one action.
How to use Proportion Calculator
- Enter your figures: Fill in the fields above. Leave anything optional blank and a sensible default is used.
- Pick your units: Switch between metric and imperial if the calculation involves units.
- Read the result: The answer updates immediately, with the breakdown shown so you can check the working.
Frequently asked questions
- Are my numbers sent anywhere? — No. The calculation runs in your browser. Salary, loan and health figures never leave the device.
- Can I rely on this for a formal decision? — Treat Proportion Calculator as a quick indication. For anything binding — a mortgage, a tax return, a medical decision — confirm with a qualified professional.
- Does it support metric and imperial? — Yes, where the calculation involves units you can switch between them and the result converts with you.
- Why does my answer differ from another site? — Usually a different formula variant or rounding step. Check the inputs match before assuming one is wrong.