zacdaddytools
Compare two values symmetrically and see their absolute and percentage difference.
Neither value is treated as the original or reference value.
Percentage difference
22.222222%
20 ÷ 90 × 100 = 22.222222%.
Percentage difference compares two values without treating either one as the starting or reference value. It first finds the absolute distance between them, then expresses that distance relative to their average.
This makes it useful for comparing two measurements, estimates, test results or observations that have equal status. Reversing Value A and Value B produces the same percentage difference.
Subtract one value from the other and use the absolute result. Add the values and divide by two to find their average. Finally, divide the absolute difference by the magnitude of that average and multiply by 100.
Using the magnitude of the average keeps the percentage non-negative when both inputs are negative. If the average is zero, the percentage is undefined because the formula would require division by zero; the tool still shows the absolute difference and average.
Absolute difference: |80 − 100| = 20.
Average: (80 + 100) ÷ 2 = 90.
Percentage difference: 20 ÷ 90 × 100 = 22.22%.
Percentage change measures movement from an original value to a new value, so the order matters and the original value is the denominator. Percentage difference is symmetric: both values contribute equally through their average, so changing their order does not change the answer.
Use percentage change for growth, reductions and before-and-after comparisons. Use percentage difference when comparing two peer measurements and neither is the natural baseline.
FAQs
Divide the absolute difference between the values by the magnitude of their average, then multiply by 100.
No. Percentage change uses an original value as the reference. Percentage difference treats both values symmetrically.
No. Reversing Value A and Value B leaves the absolute difference, average and percentage difference unchanged.
The absolute difference and average are both zero, but the percentage difference is undefined because division by zero is not possible.
Yes. Decimal and signed values are supported. A zero average produces an undefined percentage rather than Infinity or NaN.