Percentage calculator
Three everyday percentage questions in one place. Fill in any of the boxes below and the answer updates instantly.
What is X% of Y?
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X is what percent of Y?
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Percentage change from A to B
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Results are estimates for information only, not financial or tax advice.
How it works
Formula
X% of Y = Y × X ÷ 100
X as % of Y = X ÷ Y × 100
% change = (B − A) ÷ A × 100
A positive change is an increase; a negative change is a decrease.
Worked example
- 15% of 200 = 200 × 15 ÷ 100 = 30
- 30 is what % of 200? 30 ÷ 200 × 100 = 15%
- From 80 to 100: (100 − 80) ÷ 80 × 100 = +25%
Frequently asked questions
Why is a 50% drop not undone by a 50% rise?
Because each percentage is taken from a different starting value. 100 minus 50% is 50, but 50 plus 50% is only 75. To get back to 100 from 50 you need a 100% increase.
What is the difference between percent and percentage points?
If an interest rate moves from 4% to 5%, it rose by 1 percentage point, but by 25% in relative terms (1 ÷ 4 × 100).
How do I add a percentage to a number?
Multiply by (1 + percent ÷ 100). For example, 200 plus 15% is 200 × 1.15 = 230.