Percentage calculator
Work out a percentage of a number, what percent one number is of another, or the percent change between two values.
🔒 Everything runs in your browser. Nothing you choose or type is uploaded. How to verify
How to use it
- Choose the question you want answered.
- Enter the two values.
- Read the answer, which updates as you type.
Handy for
Working out discounts, exam scores, price changes and shares of a total.
Good to know
A rise of 50 percent followed by a fall of 50 percent does not bring you back to the start, because the second percentage applies to a larger number.
Privacy: where the work happens
Everything you enter or choose is processed by JavaScript in your browser and never sent anywhere. Only the page code, and any library this tool needs, is downloaded from cdnjs or jsDelivr.
Questions
How is percent change calculated?
It is the new value minus the old value, divided by the old value, times 100.
What if the old value is zero?
Percent change from zero is undefined, so the calculator asks for a non-zero starting value.