Percentage Calculator — Free Online Tool
Percentages show up everywhere — sales tax, discounts, tips, grades, and investment returns. This calculator handles the three percent problems people actually ask about, with instant answers.
What is the Percentage Calculator?
A percentage is just a fraction of 100. The word comes from the Latin per centum, meaning “by the hundred.” Because so many everyday numbers are expressed this way — a 20% tip, a 7% raise, a 35% sale — being able to move fluently between a percent and its underlying value is one of the most useful math skills you can have.
This tool offers three modes. “X% of Y” finds a portion (20% of 150 = 30). “X is what % of Y” finds the share one number represents (30 is 20% of 150). “Percent change” measures growth or shrinkage between two values, the basis of everything from stock returns to weight-loss tracking.
How to use this calculator
- Choose the calculation mode from the dropdown.
- Enter the first value (X) and the second value (Y).
- Click Calculate to see the answer.
- Switch modes to solve a different type of percent problem.
Formula
Frequently asked questions
What is 20% of 150?
30. Divide 20 by 100 to get 0.20, then multiply by 150.
How do I calculate percent increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Our “percent change” mode does this for you.
What is the difference between percent and percentage points?
A rise from 20% to 25% is a 5-percentage-point increase, but a 25% relative increase (5 ÷ 20). They measure different things.
Can percentages be over 100%?
Yes. 150% of 80 is 120. Percent change can also exceed 100% — doubling is a 100% increase, tripling is 200%.