Percentage Calculator
Work out a percentage of a number, percentage increase or decrease, or the difference between two values, free in your browser.
Enter Values
How to use this calculator
- Enter the percentage and the number.
- Press Calculate to see the result.
How it works
This finds a percentage of a number: result = (percent ÷ 100) × value. For example, 15% of 200 means 0.15 × 200.
Worked example
15% of 200. 0.15 × 200 = 30.
Common mistakes
- Mixing up 'X% of Y' with 'X is what % of Y' — they answer different questions.
- Adding percentages of different totals as if they share one base.
Frequently asked questions
How do I work out a percentage increase?
Add the percentage to 100% first — a 15% increase on 200 is 115% of 200 = 230. Or use the Percentage Change Calculator.
How do I turn a percentage into a decimal?
Divide by 100: 15% = 15 ÷ 100 = 0.15. To go the other way, multiply the decimal by 100.
How do I find what percent one number is of another?
Divide the part by the whole, then multiply by 100 — e.g. 30 of 200 is 30 ÷ 200 × 100 = 15%.
What's the quick way to find 10% of something?
Move the decimal point one place left: 10% of 250 is 25. Then 5% is half of that (12.5), 20% is double (50), and so on.
Related tools
- Percentage Change Calculator
- Discount Calculator
- GST Add Remove Calculator
- Basic Calculator
- Percentage Decrease Calculator
- Percentage Difference Calculator
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Cite this tool
Zerdly. (2026). Percentage Calculator. Retrieved from https://www.zerdly.com/tools/percentage-calculator/
Tip: Enter any known values to calculate the remaining results.
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