Percentage Calculator
Three calculators in one: find X% of a value, work out what percent one number is of another, and compute the percentage increase or decrease between two numbers.
About this tool
The Percentage Calculator bundles the three percentage questions people ask most into one screen. You can find X percent of a value, work out what percent one number is of another, and measure the increase or decrease between two numbers.
Each calculator sits in its own panel and updates live, so there is no mode-switching. It is useful for discounts, tips, grades, tax, statistics and any everyday sum where percentages are involved.
How to use
- For "X% of Y", enter the percentage and the value to get the result.
- For "X is what percent of Y", enter the two numbers to see the ratio as a percent.
- For increase or decrease, enter the starting and ending values to get the percent change.
- All three panels recalculate instantly as you type — no button to press.
- Read the labelled result, which marks a change as an increase or a decrease.
Features
- Three independent calculators visible at once, no mode toggle needed.
- Percent-of, what-percent and percent-change in a single tool.
- Signed percent change that clearly shows increase versus decrease.
- Accepts decimals and both comma and dot as the decimal separator.
- Live results that update on every keystroke.
- Clean, readable output suitable for quick everyday maths.
Frequently asked questions
Is anything I type sent online?
No. Every calculation happens locally in your browser, so the numbers you enter stay on your device.
How do I calculate a percentage discount?
Use the "X% of Y" panel: enter the discount percent and the original price to see the amount saved, then subtract it from the price.
How is percentage change calculated?
It is the difference between the end and start values divided by the start value, expressed as a percent. A positive result is an increase, a negative one a decrease.
Can I enter decimal numbers?
Yes. Decimals are supported, and the tool accepts either a dot or a comma as the decimal point.
What does a negative percent change mean?
A negative value means the number went down; the tool labels it as a decrease so the direction is never ambiguous.