How to use the percentage calculator
- X% of Y — enter a percent and a number to get the amount (e.g. 20% of 150 = 30).
- X is what % of Y — find what proportion one number is of another.
- Increase/decrease — enter a start and end value to see the percentage change.
The formulas
- Percentage of a number: (percent ÷ 100) × number
- What percent: (number ÷ total) × 100
- Percentage change: ((new − old) ÷ old) × 100
Everyday examples
- Discount: 25% off a $80 item → you save $20, pay $60.
- Tip: 15% of a $40 bill = $6.
- Grade: 45 out of 60 = 75%.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percent by 100, then multiply by the number. For 20% of 150: 0.20 × 150 = 30.
How do I find percentage increase?
Subtract the old value from the new, divide by the old value, then multiply by 100.
Is it free?
Yes, completely free with no sign-up.