Percentage Calculator
Work out X% of a number, what percent one number is of another, and percentage increase, decrease or difference.
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Percentage formulas
- X% of Y = Y × X ÷ 100
- X is what % of Y = X ÷ Y × 100
- Percentage change = (new − old) ÷ old × 100
- Percentage difference = |A − B| ÷ ((A + B) ÷ 2) × 100
Working out a sale price? The discount calculator handles stacked discounts and tax. Pricing products? See the profit margin calculator.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. 15% of 200 = 200 × 15 ÷ 100 = 30.
How do I calculate percentage increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. From 80 to 100: (100 − 80) ÷ 80 × 100 = 25% increase.
What is the difference between percentage change and percentage difference?
Percentage change compares a new value with an old one, so direction matters (80 to 100 is +25%, 100 to 80 is −20%). Percentage difference compares two values with no "before", dividing by their average, so 80 and 100 differ by 22.2% either way.
Why is a 50% drop not undone by a 50% rise?
Because each percentage is of a different base. 100 down 50% is 50; 50 up 50% is only 75. To get back to 100 you need a 100% rise.