Percentage calculator
Find a percentage of a number, what percent one number is of another, or the change between two values. Results update as you type.
Result
Calculated in your browser. Nothing is sent anywhere.
How it works
A percentage is a fraction of 100. Three questions cover almost every everyday case:
X% of Y = Y × X ÷ 100X as % of Y = X ÷ Y × 100change = (new − old) ÷ old × 100Worked example
What is 15% of 200?
- 200 × 15 = 3000
- 3000 ÷ 100 = 30
- 15% of 200 is 30
Frequently asked questions
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. 30 out of 200 is 30 ÷ 200 × 100 = 15%.
How do I increase a number by a percentage?
Multiply it by 1 plus the percentage as a decimal. 200 increased by 15% is 200 × 1.15 = 230; decreased by 15% it is 200 × 0.85 = 170.
Why does +50% and then −50% not bring me back?
Each change applies to a different base. 100 + 50% = 150, and 150 − 50% = 75. To undo a 50% rise you need a 33.3% fall.
Is my data sent to a server?
No. The calculation runs in your browser; the numbers only appear in the page address so you can share them.