Free online calculator
Percentage Calculator
Solve common percentage questions: a percentage of a value, one value as a percentage of another, or percentage change.
Free calculator
Percentage Calculator
Enter your values to see the result.
Formula explained
Percentage of value = rate × value ÷ 100. A as % of B = A ÷ B × 100. Percentage change = (new − old) ÷ |old| × 100.
Worked example
Select a mode, then enter the two requested values. For example, 25% of 800 is 200.
Limitations and assumptions
Percentage change is undefined when the original value is zero. Negative inputs are allowed where mathematically meaningful.
Frequently asked questions
Can I calculate a decrease?
Yes. Percentage-change mode returns a negative result when the new value is lower.