Percentage calculator
The everyday percentage questions in one place — what is X% of Y, X is what percent of Y, the percentage change between two numbers, and increasing or decreasing a number by a percentage. Live as you type, fully offline.
Open Percentage calculator →What is the percentage calculator?
A free percentage calculator that puts the everyday percentage questions in one place: what is X% of Y, X is what percent of Y, the percentage change between two numbers, and increasing or decreasing a number by a percentage. Each answer updates live as you type, entirely in your browser and fully offline.
How to use Percentage calculator
- Find the right box — Each of the four cards answers a different question — pick the one that matches what you need to work out.
- Type your numbers — Fill in the two values in that card. The result appears the moment both numbers are entered — no button to press.
- Read the result — For percentage change you'll see whether it's an increase or decrease, and the increase/decrease card shows both the higher and lower figure.
- Pick up where you left off — Your entries are saved on your device, so the numbers are still there when you reopen the tool.
Frequently asked questions
Which box do I use for a discount or a tax?
Use 'increased & decreased by X%' — it shows the number with the percentage added and with it taken away, so you can read off the after-tax or after-discount figure in one place.
How is percentage change calculated?
It compares the second number to the first, divides by the size of the first, and shows the result as a percentage with a + or - and an 'increase' or 'decrease' label.
Are my numbers sent anywhere?
No. Everything is worked out live in your browser and nothing is sent anywhere. Your entries are saved only on your own device.
Does it handle decimals?
Yes. The inputs accept decimal values and results are rounded to six decimal places, so fractional percentages work fine.
Do I need to press a calculate button?
No. Each answer recalculates instantly as you type, so there's nothing to click.
Tips
- Use the 'increase & decrease' card to read both a price-with-tax and a price-with-discount at once.
- For a percentage change, put the original figure first and the new figure second to get the right sign.
- Your last entries stay saved on your device, so it's quick to tweak one number and re-check.