How to calculate percentages
A percentage is just a fraction of 100. These three tools cover the everyday questions:
- X% of Y: multiply Y by X and divide by 100. (20% of 150 = 30)
- X is what % of Y: divide X by Y and multiply by 100. (30 of 150 = 20%)
- Percent change: subtract old from new, divide by old, ×100. (80→100 = +25%)
Frequently asked questions
What's the difference between percent change and percentage points?
Going from 10% to 12% is a 2 percentage-point rise, but a 20% increase. This tool shows percent change.
Can percent change be negative?
Yes — if the new value is lower than the old, you'll see a negative percentage (a decrease).