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Percentage calculator
Four percentage questions cover almost everything people need, and this handles all four.
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Choose the question, then put in the two numbers.
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Figures checked
This calculator is arithmetic only and uses no statutory figures. This is general information, not professional advice.
The trap with increases and decreases
Adding twenty per cent and then taking twenty per cent off does not return you to where you started. One hundred increased by twenty per cent is one hundred and twenty; twenty per cent off that is ninety-six. The percentage is applied to a different number each time, which is also why taking twenty per cent off a VAT-inclusive price gives the wrong answer.
Percentage change
Percentage change is always measured against the starting figure, not the finishing one. Going from forty to fifty is a twenty-five per cent increase; going from fifty back to forty is a twenty per cent decrease, even though the gap is ten either way.