Percentage Calculator
Find a percentage of a number, what percent one number is of another, or percent change.
Calculate
Result
- Worked out as a ÷ 100 × b, where a is the first number and b the second.
Runs in your browser — nothing you enter leaves this device.
About this tool
What it does
This calculator answers the three percentage questions people ask most: what is X% of a number, what percentage one number is of another, and by how much a value went up or down. It uses exact decimal arithmetic, so results never show floating-point noise like 0.30000000000000004.
How to use it
- Choose the question: "% of", "is what %" or "% change".
- Enter the two numbers. The labels change to match the question.
- Read the result, with the formula used shown underneath.
Limits and your data
- A percentage change from zero is undefined, so the calculator says so instead of showing infinity.
- Results are shown to at most six decimal places.
- The numbers you enter are calculated on this page and never sent anywhere or saved.
Questions
How do I find a percentage increase?
Choose "% change", enter the old value as From and the new value as To. A rise shows as a positive percentage, a fall as a negative one.
Why is a 50% rise followed by a 50% fall not back to the start?
The fall is 50% of the larger number. ₹100 up 50% is ₹150; down 50% from ₹150 is ₹75. Percentages of different bases do not cancel out.
How do I work out a discount?
Choose "% of" with the discount rate and the price to get the amount taken off, then subtract it from the price.