How it works
To find a percentage of a number, divide the percentage by 100, then multiply by the number. To find what percentage a part represents, divide the part by the whole and multiply by 100. For percentage change, divide the difference by the original positive value.
(percentage / 100) × numberWorked example
15% of 200: 15 / 100 = 0.15, then 0.15 × 200 = 30. An increase from 200 to 250 is (250 − 200) / 200 × 100 = 25%.
Frequently Asked Questions
Can a percentage exceed 100%?
Yes. 150% of 200 equals 300. A percentage above 100 represents more than the original whole.
How do I calculate a decrease?
Select Percentage change and enter the old and new values. A fall from 100 to 80 gives −20%.
Why is division by zero unavailable?
A ratio needs a nonzero whole. Percentage change needs a positive starting value; a zero baseline has no defined percentage change.
How are results rounded?
Displayed numbers use up to six decimal places. Calculations use unrounded JavaScript numbers; very small values may use scientific notation.