Percentage Calculator
Percentages, percent change, discounts and reverse percentages — with the formula shown for every result.
Numbers you enter are calculated in your browser and never sent to a server.
Find the value of a percentage of a base number.
Result
30
15% of 200
Formula
200 × 15 ÷ 100
- Base
- 200
- Percent
- 15%
Examples
What is this tool?
A free percentage calculator with five modes: percent of a number, what percent one value is of another, percent change, increase/decrease by a percentage, and reverse calculation to find the whole.
How to use
- Pick the mode that matches your question.
- Enter the values — results update instantly with the formula used.
- Copy the result or start from one of the common examples.
Use cases
- Working out sale prices and discounts while shopping.
- Computing growth or decline rates for reports.
- Reverse-calculating an original price before tax or discount.
Notes
- All calculations happen locally in your browser.
- Division by zero is handled with a clear error message.
FAQ
How do I calculate a discount?
Use "Increase / decrease" with the decrease operation: enter the original price and the discount percentage to get the final price and how much you save.
How is percent change calculated?
The change mode computes (new − original) ÷ |original| × 100 and tells you whether the value increased or decreased.
Is my input sent to a server?
No. All calculations run locally in your browser.
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