Percentage Calculator — Find a Percentage, Percentage Change and More
A percentage calculator helps you answer everyday maths questions quickly: how much is 20% off, what share did you score in a test, or how much has a price gone up?
Percentage Calculator
What this tool does
This tool handles the three percentage calculations people use most often. It does not store your numbers anywhere: every calculation happens in your browser, so you can use it for homework, shopping, budgeting or work without signing up.
How to use it, step by step
- Choose the type of calculation from the menu.
- Type the first number, then the second number.
- Press Calculate and read the answer, including the exact numbers you entered so you can check them.
- If you change a number, press Calculate again for the new result.
Worked example
A jacket costs 80 and is reduced by 25%. To find the saving, work out 25% of 80: 80 × 25 ÷ 100 = 20. The saving is 20, so the final price is 80 − 20 = 60. Our Discount Calculator does this in one step, but this percentage tool shows the same idea in its general form.
Common mistakes
- Mixing up the base: “20% of 200” and “20% more than 200” are different. The first is 40; the second is 240.
- Adding percentages directly: a 20% rise followed by a 20% fall does not return to the start, because the second percentage is taken from a larger number.
- Forgetting the sign: a negative percentage change means a decrease, not an error.
Frequently asked questions
How do I find 15% of a number by hand?
Multiply the number by 15 and divide by 100. For 15% of 300: 300 × 15 ÷ 100 = 45.
What is the difference between percentage and percentage points?
If a rate rises from 20% to 25%, it has risen by 5 percentage points, but by 25% in relative terms (5 ÷ 20 × 100).
Can percentages be over 100%?
Yes. A result over 100% simply means the first number is larger than the second, or a value has more than doubled.
Why does my answer have many decimals?
Percentages do not always divide neatly. Rounding to one or two decimal places is usually sensible for money and everyday use.