Rule of three calculator
Solve a proportion and display the result and multiplier.
How to use rule of three calculator
Enter the requested values and run the calculation. The main calculation stays on your device and the page explains the result.
Practical use
Change one value at a time to compare scenarios. Review the intermediate figures as well as the headline result before making a decision.
Advice and limitations
This tool provides a practical estimate. Check the source values, units and assumptions, and seek qualified advice whenever the result affects health, law, finance or safety.