How to use the Percentage Calculator
The percentage calculator answers the four most common percent questions: percent of a number, percent change, adding a percent and removing a percent.
Open the Percentage Calculator →
The formula
Percent of a number = number × percent ÷ 100. Percent change = (new − old) ÷ old × 100. Add a percent: number × (1 + p ÷ 100). Remove a percent: number × (1 − p ÷ 100).
Worked example
15% of 80 = 12. From 50 to 65 is a 30% increase. Adding 20% to 150 gives 180. Removing 20% from 120 gives 96.
Tips for better results
- Pick the question first, then fill in the two numbers.
- To undo "add 20%", divide by 1.20, not subtract 20%.
Common mistakes to avoid
- Dividing by the new value instead of the old value for percent change.
- Adding and then removing the same percent and expecting the original number.