Percentage Difference Calculator
Find the percentage difference between two values — a symmetric measure that does not depend on which number you call "original." Enter both values and get the percentage difference, absolute gap, and midpoint.
Symmetric — does not depend on which value you call the original
- 1
Absolute difference
|80 − 100| = 20 - 2
Average of both values
(|80| + |100|) ÷ 2 = 90Using the average (not one specific value) makes the result symmetric — order of V1 and V2 does not matter. - 3
Percentage difference
20 ÷ 90 × 100 = 22.22
How does this calculator work?
Percentage Difference = |V1 − V2| ÷ ((|V1| + |V2|) / 2) × 100. This symmetric formula uses the average of both values as the reference, so swapping V1 and V2 gives the same result. Use it when comparing two measurements with no defined "original."
Formula
How this is calculated
Percentage difference is a symmetric measure: it compares the absolute gap between two values to their average (midpoint). Because the denominator is the mean of both values rather than one specific starting value, the result is the same no matter which you call V1 or V2. This makes it ideal when neither value is an original or reference — for example, comparing two experimental measurements, two prices, or two populations where no single one serves as the baseline.
The formula divides the absolute difference |V1 − V2| by the mean of the absolute values ((|V1| + |V2|) / 2), then multiplies by 100 to express the result as a percentage. When both values have the same sign and are both positive, the average is simply (V1 + V2) / 2.
Percentage difference is not the same as percentage change. Percentage change is directional and always divides by the original (starting) value, so swapping V1 and V2 gives a different answer. Use percentage change when one value is clearly the "before" and the other is "after."
Frequently asked questions
Percentage difference measures how two values compare relative to their average, expressed as a percentage. Use it when neither value is a baseline or original — for example, comparing two test results or two prices where no one value is the "starting point."
Percentage change divides by the original (starting) value, so order matters. Percentage difference divides by the average of both values, so it is symmetric — the result is the same regardless of which is V1 and which is V2.
If one value is zero and the other is not, the average is half of the non-zero value, and the percentage difference equals 200%. If both are zero, the difference is undefined (no meaningful comparison).
Also known as
TG we-Calculate Editorial Team. (2026). Percentage Difference Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/percentage-difference-calculator
TG we-Calculate Editorial Team. "Percentage Difference Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/percentage-difference-calculator.
TG we-Calculate Editorial Team, "Percentage Difference Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/percentage-difference-calculator
@misc{wecalculate_percentage_difference_calculator, title = {Percentage Difference Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/percentage-difference-calculator}}, year = {2026}, note = {TG we-Calculate} }
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