How to calculate a percentage
- Choose the kind of question, such as X% of Y.
- Type the two numbers.
- Read the answer and the working underneath.
About this tool
Pick the question you have, type two numbers, and the answer appears as you type. One page covers the sums people search for most: a percent of a number, what percent one number is of another, the number when you know the percent, the change between two values, and adding or removing a percent. Each answer shows its formula.
Common questions
How do I find 15% of 200?
Multiply 15 by 200 and divide by 100. The answer is 30. Choose 'X% of Y' and type 15 and 200.
Why does adding 20% and then removing 20% not bring me back?
The second 20% is taken from a bigger number. After adding 20% to 100 you have 120, and 20% of 120 is 24, which leaves 96. To undo +20% you need -16.67%.
Can I use decimals and negative numbers?
Yes. Both work. Percent change from a negative start uses the size of the starting value, so a fall from -10 to -5 counts as a 50% rise.
Is it free to use?
Yes. There's no sign-up, and you can use it as often as you like.
Is my text uploaded anywhere?
No. This tool runs inside your browser, so what you enter stays on your device.
Do I need to install anything?
No. It works in your browser on a computer or a phone.