Find the percentage difference between two numbers. Unlike percentage change, this compares both numbers to their average, so the answer stays the same no matter which order you enter them.
The absolute difference between the two values is found.
That is divided by the average of the two values, not by either one of them.
Because the base is the average, swapping the two inputs gives an identical answer.
Percentage difference: |A − B| ÷ ((A + B) ÷ 2) × 100
Base: The average of the two values
Comparing two measurements: 40 and 60.
Value A: 40
Value B: 60
Difference: |40 − 60| = 20
Average: (40 + 60) ÷ 2 = 50
Percentage difference: 20 ÷ 50 × 100 = 40%
Answer: 40% difference
How is this different from percentage change?
Percentage change has a direction — it measures a move from an old number to a new one, so 40 to 60 is a 50% increase. Percentage difference has no direction, and uses the average as its base, giving 40%. Use change for before-and-after, and difference for comparing two separate measurements.
Can the percentage difference exceed 100%?
Yes, when the two numbers are far apart and one is close to zero. It is capped at 200% only when one number is zero and both are positive.