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Percentage Calculator
Three percentage questions, one tool: a percentage of a number, one number as a share of another, and percentage change.
Answer
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How it works
X% of Y = X ÷ 100 × Y X is what % of Y = X ÷ Y × 100 % change = (Y − X) ÷ X × 100
Worked examples: 20% of 250 = 50. 50 is 25% of 200. And a rise from 200 to 250 is a 25% increase, because (250 − 200) ÷ 200 × 100 = 25%.
Frequently asked questions
How do I find a percentage of a number?
Divide the percentage by 100, then multiply by the number. For 20% of 250: 20 ÷ 100 × 250 = 50.
How do I find what percentage one number is of another?
Divide the first number by the second and multiply by 100. For 50 out of 200: 50 ÷ 200 × 100 = 25%.
What does a negative percentage change mean?
It means a decrease. A fall from 250 to 200 is (200 − 250) ÷ 250 × 100 = −20%, a 20% decrease.
What if the starting number is zero?
Percentage change from zero is undefined (you would divide by zero). This tool shows 0 in that case rather than an error.