Percentage Calculator
Calculate percentages, percentage change, increase/decrease, and reverse percentages.
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What is X% of Y?
What is a Percentage Calculator?
A percentage calculator helps you compute percentages quickly and accurately. It supports common percentage calculations used in finance, shopping, statistics, and everyday life.
This tool features:
- Four calculation modes — Percent of a number, proportion, change, and reverse percentage.
- Formula display — See how each result is calculated step by step.
- Instant results — Results update in real-time as you type.
How to Use
- Select a mode — Click one of the four calculator modes above.
- Enter values — Fill in the input fields for the selected mode.
- Read the result — The result updates automatically as you type.
Frequently Asked Questions
How do I calculate percentage of a number?
Multiply the number by the percentage divided by 100. For example, 15% of 200 = 200 × 15/100 = 30. Use the "What is X% of Y?" mode.
How do I calculate percentage change?
Subtract the original value from the new value, divide by the original value, and multiply by 100. A positive result means an increase; negative means a decrease.
What is reverse percentage?
Reverse percentage finds the original number when you know a part and its percentage. For example, if 30 is 15% of a number, the number is 30 / (15/100) = 200.
Is this tool free to use?
Yes. All processing happens entirely in your browser. No data is sent to any server.