What is the Percentage Calculator?
The Percentage Calculator answers the three questions people ask most about percentages in one place. Enter two numbers and it shows what X percent of Y is, what percentage X is of Y, and the percentage change when a value goes from X to Y. It removes the need to remember formulas, which makes it useful for discounts, grades, tips, taxes and growth figures.
How to use the Percentage Calculator
- Type your first number in the X box and your second number in the Y box.
- Read the first line to see X percent of Y.
- Read the second line to see what percentage X is of Y.
- Check the third line for the percentage increase or decrease from X to Y.
Benefits and use cases
- Shoppers working out the real price after a discount.
- Students checking marks, scores and exam results.
- Small business owners comparing sales and expenses between two periods.
- Anyone calculating tips, commissions, interest or tax shares.
Tips for best results
To work out a discount, enter the discount rate as X and the original price as Y to see the amount you save, then subtract it from the price. To compare two years, enter the earlier figure as X and the later figure as Y. Always check that you have placed the numbers in the right boxes, because swapping them changes the answer.
ToolZen tools run in your browser, so your input is not uploaded to a server. Bookmark this page and come back whenever you need it. There is nothing to install and no account to create.
Frequently asked questions
How is percentage change calculated?
It is the new value minus the old value, divided by the old value, multiplied by 100.
What does a negative percentage change mean?
A negative number means the value decreased from X to Y.
Can I use decimals?
Yes. Enter any number, including decimals and negative values.
Why does it sometimes show Infinity or NaN?
Dividing by zero is undefined, so a change from zero, or a percentage of zero, cannot be calculated.