Find how much two values differ in percentage terms. Ideal for comparing results, prices, or performance metrics.
Compare two values and find their percentage difference
Formula:
Percentage Difference = (|A − B| ÷ ((A + B) ÷ 2)) × 100Percentage difference shows the relative gap between two values based on their average, not on a single starting point. It’s common in science, data analysis, and economics where you want a fair, symmetric comparison.
(|A − B| ÷ ((A + B) ÷ 2)) × 100
Need a directional change from an original value instead? Try the Percentage Change Calculator.
Example: compare 48 and 57.6.
For old→new comparisons instead, see the Percent Increase or Percent Decrease tools.
You can compute percent difference quickly in a spreadsheet:
Formula: =ABS(B2-A2)/((A2+B2)/2) then format as %.
Safe version: =IF((A2+B2)=0,"",ABS(B2-A2)/((A2+B2)/2))
Compare 100 vs 120
Result: 18.18% difference
Compare 80 vs 100
Result: 22.22% difference
Prices: $2.40 vs $2.52
Result: 4.92% difference
Scores: 72 vs 90
Result: 22.22% difference
Negatives: −40 vs −50
Result: 22.22% difference (relative to their average)
It measures how much two values differ as a percentage of their average. It’s symmetric, so swapping A and B gives the same result.
Percentage change compares a new value to an original baseline (direction matters). Percentage difference compares two values relative to their average and is not directional.
Percent Difference = (|A − B| ÷ ((A + B) ÷ 2)) × 100.
Yes. The absolute difference handles sign, and the average sets the scale. If the average is 0 (e.g., +x and −x), the result is undefined.
Use =ABS(A2-B2)/((A2+B2)/2) and format as %. Wrap with IF for safety: =IF((A2+B2)=0, "", ABS(A2-B2)/((A2+B2)/2)).
Use percent difference to compare two independent values (prices at two stores, two measurements). Use percent change to measure movement from a specific starting value.
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