Percentage Calculator
Three calculations in one · Page last updated August 2026
Results
Result
How the Percentage Calculator Works
This tool covers the three percentage calculations people need most often: finding a percentage of a number (X% of Y), finding what percent one number is of another (X is what % of Y), and finding the percent change between two numbers. Pick a mode and the input labels update to match.
All three use standard percentage math and are calculated instantly in your browser.
Frequently Asked Questions
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. Choose "X is what % of Y" mode, enter the two values, and the calculator does this for you.
How is percent change calculated?
Percent change is (new value - original value) divided by the absolute value of the original value, times 100. A positive result is an increase, a negative result is a decrease.
Why does percent change use the absolute value of the original number?
Using the absolute value keeps the sign of the result meaningful (increase vs. decrease) even when the original value is negative, which is the standard convention for percent change.