How to use this tool
Select Percent of, Percent change, or What percent. Enter your numbers to calculate the answer, compare values, and see the formula behind the result.
Quick steps
- Choose percentage of a number, percent change or what percentage.
- Enter the two values for the selected calculation.
- Read the live result and the formula used to calculate it.
Practical tip
A 20% increase followed by a 20% decrease does not return the original value: 100 becomes 120, then 96. Percentage change uses the original value as the denominator.
Common questions
What is 15% of 200?
Multiply 200 by 15 divided by 100 to get 30.
How do I find a percentage increase?
Subtract the original value from the new value, divide by the original, then multiply by 100.
Can I calculate a percentage change from zero?
Not as a finite relative percentage. The tool flags a zero original value, where the standard ratio is undefined.