Choose the type of percentage calculation, enter two values, and get a clearly formatted result with the formula used.
Calculate a percentage
Select a calculation type, then enter both values.
Percentage result
How to use the Percentage Calculator
- Select the calculation that matches your question.
- Enter both values. Decimals and negative numbers are allowed.
- Select Calculate or press Enter to see the result.
- Use Reset to clear the form and return to the first mode.
Percentage formulas
Worked examples
| Question | Working | Result |
|---|---|---|
| What is 20% of 500? | (20 ÷ 100) × 500 | 100 |
| 50 is what percent of 200? | (50 ÷ 200) × 100 | 25% |
| Increase from 100 to 125 | ((125 − 100) ÷ 100) × 100 | 25% |
| Decrease from 200 to 150 | ((200 − 150) ÷ 200) × 100 | 25% |
| Difference between 100 and 120 | 20 ÷ 110 × 100 | 18.1818% |
Understanding negative results
A negative percentage increase means the second value moved downward relative to the first. A negative percentage decrease means it moved upward. The percentage-difference mode is always non-negative because neither value is treated as the starting point.
Frequently asked questions
What is the difference between percentage change and percentage difference?
Percentage change treats one value as the original baseline. Percentage difference treats both values equally and divides their absolute difference by their average magnitude.
Can percentages be greater than 100%?
Yes. A part can be greater than the whole, and a change or difference can exceed 100%.
Can I enter negative or decimal values?
Yes. Decimal and negative values are accepted. For change calculations involving negative originals, the calculator uses the magnitude of the original value so the direction of movement remains meaningful.
Why can’t the original or comparison value be zero?
A percentage ratio requires division by a baseline. Division by zero is undefined, so the calculator shows an error for those modes.
How are results rounded?
Results are displayed with up to four decimal places and no unnecessary trailing zeros. Calculations use the browser’s full numeric precision before display formatting.