Percentage Calculator
All calculations run instantly in your browser.
What is X% of Y?
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X is what % of Y?
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Percentage change from X to Y
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Increase / Decrease Y by X%
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X is X% more/less than what?
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Part as % of Total
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About
The Percentage Calculator solves the most common percentage problems: finding what percentage one number is of another, calculating a percentage of a number, computing percentage increase or decrease between two values, and reversing a percentage to find the original amount. Results update as you type.
How to use
- 1 Choose the calculation type from the tabs: % of Number, % Change, Ratio, or Reverse %.
- 2 Enter your numbers in the input fields.
- 3 The result is calculated and displayed instantly.
- How do I calculate what percentage one number is of another?
- Use the "% of Number" tab. Enter the part and the whole — the tool divides the part by the whole and multiplies by 100. For example, 45 out of 180 = (45 ÷ 180) × 100 = 25%. This is useful for exam scores, sales targets, and any ratio expressed as a percentage.
- How do I calculate percentage increase or decrease?
- Use the "% Change" tab. Enter the original value and the new value. The formula is ((new − original) ÷ original) × 100. A positive result is an increase; a negative result is a decrease. For example, from 80 to 100 is a 25% increase.
- What does Reverse % mean?
- Reverse % finds the original number before a percentage was applied. For example, if you know that 75 is 60% of a number, the reverse calculation gives you the original: 75 ÷ 0.60 = 125. This is useful for finding pre-tax prices, original prices before a discount, or base values in financial calculations.