How to use this calculator
Choose the calculation before entering your numbers: a share and a change answer different questions. In change mode, the first value is always the starting point.
A zero whole cannot be used for a share, and a zero starting value has no defined percentage change. For ordinary growth comparisons, use positive starting values; negative baselines can produce counterintuitive signs.
The formula
Percentage of a number = A × B ÷ 100. Share = A ÷ B × 100. Change = (B − A) ÷ A × 100.
A worked example
20% of 150 is 30. A change from 150 to 180 is a 20% increase.
Read our calculator disclaimer. Found an issue? Send feedback.