TOOL · CALCULATOR
Percentage calculator
Four percentage problems, solved: what is X% of Y, what percent one value is of another, applying a discount or increase, and the change between two values. Type and the answer appears.
What is X% of Y?
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X is what percent of Y?
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Increase or decrease Y by X%
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Percent change from A to B
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Processed in your browser — your files never leave your computer.
How it works
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Pick the calculation
Four calculators live on the same page — scroll to the question that matches your case.
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Fill in the numbers
Type the values into the fields. Comma or dot for decimals — both work.
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Read the result
The answer appears instantly, rounded to two decimal places at most. Change a number and the result follows.
Frequently asked questions
How do I calculate a 15% discount?
Use the third calculator: pick "decrease", enter the price and 15. It shows the final value with the discount applied.
How do I find what percent one value is of another?
Second calculator: "X is what percent of Y?". Example: 30 out of 120 is 25%.
What is the difference between an increase and percent change?
An increase applies a percentage you already know to a value. Percent change finds the percentage between two values — from 80 to 100, for example, the change is +25%.
Can I type decimals with a comma?
Yes — comma or dot, both work. The result follows your page language.
Are the values I type sent anywhere?
No. The math happens in your browser, with no account, no history and no network. Close the tab and it is gone.
Does it work for interest rates?
For simple interest over one period, yes: use "increase Y by X%". Compound interest (period over period) means repeating the calculation each period.