Percentage Difference Calculator
Calculate the symmetric percentage difference between two values, treating neither value as the "before" baseline.
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- Accurate results
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- Works on all devices
Your result
22.22%
Percentage difference
AI explanation
Formula
Difference % = |A − B| / ((|A| + |B|) / 2) × 100Worked example
80 vs 100
| Field | Value |
|---|---|
| First value | 80 |
| Second value | 100 |
| Percentage difference | 22.22 |
Assumptions
- Unlike percentage change, this treats both values symmetrically — swapping A and B gives the same result, since the base is the average of the two absolute values, not either value alone.
- At least one of the two values must be non-zero.
Frequently asked questions
How is percentage difference different from percentage change?
Percentage change is directional — it treats one value as "before" and divides by that value. Percentage difference is symmetric — it divides by the average of both values, so it gives the same result regardless of which value you enter first.
When should I use percentage difference instead of percentage change?
Use percentage difference when comparing two independent measurements or estimates where neither is clearly the "original" — for example, comparing two lab results or two price quotes. Use percentage change when one value is genuinely a starting point that changed over time.
Can percentage difference be negative?
No — because it uses an absolute difference in the numerator, percentage difference is always zero or positive.