AllEasyToolsLower secondary
Proportion calculator
Proportion calculator: formula, units and explained result. No account required. Processing stays in your browser.
a / b = c / x → x = b × c / a
Direct proportion; a must be nonzero.
How to use this calculator
- Identify the quantities and convert them to the units shown.
- Apply the formula first, then compare with the substitution and result.
- Check the assumptions and whether the order of magnitude makes sense.
Levels are approximate topic groupings, not a complete curriculum for every country. Numerical results are rounded and may lose precision for extreme or nearly singular inputs.
A practical example
Use these sample inputs to check the calculation before entering your own values.
- a
- 2
- b
- 6
- c
- 5
Result for this example
- Result x
- 15