Percentage Calculator
Five common percentage calculations in one tool.
Result
50
(25 / 100) × 200 = 50
Percentage formulas
- X% of Y: (X / 100) × Y
- X is what % of Y: (X / Y) × 100
- % change: ((new − old) / old) × 100
- Increase by %: X + (X × Y / 100)
- Decrease by %: X − (X × Y / 100)
Common examples
- Tip: 15% of a $80 bill = $12
- Discount: 30% off $150 = $105
- Growth: revenue from $100K to $125K = 25% increase
Privacy
Everything runs in your browser. Nothing is uploaded.
Frequently Asked Questions
What calculations does this tool do?
Five: (1) what is X% of Y, (2) X is what % of Y, (3) percent change from X to Y, (4) increase X by Y%, (5) decrease X by Y%.
How is percent change calculated?
Percent change = ((new - old) / old) × 100. Positive is an increase, negative is a decrease.
Is it free?
Yes, completely free.
Does it work offline?
Yes. Once the page loads, all calculations happen in your browser.
Can I use negative numbers?
Yes. Negative numbers work for most calculations, though 'what percent' with a negative total may give unusual results.