Compare a gap without choosing one value as the starting baseline. Enter the two values below. The result panel shows the calculation used, and the examples explain how to interpret it.
How to use the percentage difference calculator
- Identify the values required by the input labels.
- Enter percentages as whole-number rates: 15 means 15%.
- Select Calculate and read the result together with its formula.
- Check the assumptions below before applying the answer to a real situation.
Formula and method
Worked example
Compare two measurements of 90 and 110. Their absolute difference is 20, and their average is 100. Divide 20 by 100 and multiply by 100: the symmetric percentage difference is 20%.
If 90 was actually the original value and 110 the later value, percentage change would instead be 20 ÷ 90 × 100, or about 22.2222%. Choose the method according to the question, rather than whichever result is smaller.
Example calculations
| First value | Second value | Difference |
|---|---|---|
| 80 | 100 | ≈ 22.2222% |
| 100 | 80 | ≈ 22.2222% |
| 40 | 40 | 0% |
| 0 | 10 | 200% |
Input rules and limitations
This tool uses nonnegative values with at least one positive value. The mean of two zero values is zero, making the formula undefined. Other fields may define percentage difference differently; check the convention used in your assignment or report.
Display precision can be changed from two to eight decimal places. Intermediate values are not rounded, but the calculation uses standard browser floating-point arithmetic. Currency figures should be rounded according to the rules relevant to your actual transaction.
Common questions
Does the result include units?
The calculator works with numbers. Keep the same units for comparable quantities and add the appropriate unit when reporting the result.
Why does the calculator reject some inputs?
This tool uses nonnegative values with at least one positive value. The mean of two zero values is zero, making the formula undefined. Other fields may define percentage difference differently; check the convention used in your assignment or report.
Is my information sent to a server?
Calculator values stay in your browser. They are not submitted to the website’s server for calculation.
Where can I learn the related formulas?
Use the main percentage calculator for basic shares and wholes, or browse our guides for worked examples and common mistakes.
Choose the right comparison
Use the percentage change calculator for an original-to-new comparison, the percentage difference calculator when neither value is the baseline, and the percentage points calculator to subtract rates. You can also return to the main percentage calculator.