Percentage Calculator
Percent of, change and more.
Percentage Calculator at a glance
Percentage Calculator is a free online calculator you can use right now to percent of, change and more โ no account, no install and no usage limit. It runs entirely inside your browser, so whatever you enter stays on your own device.
- Price
- Free โ no trial, no paid tier, no watermark
- Sign-up
- Not required
- Where it runs
- In your browser โ nothing is uploaded to a server
- Works on
- Chrome, Safari, Firefox and Edge โ desktop, tablet and phone
- Category
- Calculators
About Percentage Calculator
The Percentage Calculator handles the three percentage questions that actually come up, without you having to remember which way round the formula goes: what is X% of Y, X is what percent of Y, and what's the percentage change from X to Y.
That third one causes the most confusion, because percentage increase and decrease aren't symmetrical. A price that rises 50% and then falls 50% does not return to where it started โ it ends up 25% below, because the decrease applies to the larger number. This catches people out constantly with discounts and investment returns.
Useful for working out discounts, tips, tax, exam marks, commission, and any figure quoted as a percentage change in a report or headline.
How to use Percentage Calculator
- Type your numbers into the fields.
- The result updates the moment you change a value.
- Adjust any input to compare different scenarios.
Frequently asked questions
How do I calculate a percentage increase?
Subtract the old value from the new one, divide by the old value, and multiply by 100. Going from 40 to 50 is (50-40)/40 x 100 = 25% increase.
Why doesn't a 50% rise then a 50% fall get me back to the start?
Each percentage applies to a different base. 100 rises 50% to 150; 50% of 150 is 75, so you land at 75 โ not 100. The fall is calculated on the bigger number.
How do I work out the original price before a discount?
Divide the sale price by (1 minus the discount as a decimal). An item costing 80 after 20% off was originally 80 / 0.8 = 100.