Reverse Calculators
Percentage Difference Calculator
Enter A and B to see absolute difference, percentage difference vs average, and percent change A→B.
Percentage difference vs percentage change
Percentage difference is a symmetric comparison: absolute difference divided by the average of A and B, times 100. Percentage change from A to B is directional: (B − A) ÷ A × 100, and needs a non-zero starting point. Use difference when neither value is the “true” baseline (two lab measurements, two quotes). Use change when A is yesterday’s price or last year’s figure. Absolute difference is shown in the same units you entered. Related share maths lives in what percentage is X of Y; sale prices use price decrease.
Worked example
A=80, B=100 → absolute difference 20; average 90; % difference ≈ 22.22%; % change A→B = +25%.
Limits and assumptions
Not a statistical confidence interval. Averaging negatives can confuse interpretation — keep signs meaningful.
Frequently asked questions
Which should I quote in a report?
If one figure is the baseline, quote % change. If both are peers, % difference is fairer.
Why do the two percentages disagree?
Different denominators — average vs starting value.
What if A is zero?
% change is undefined; % difference may still work if B is non-zero.
Absolute vs relative?
Absolute difference keeps units; percentages remove units for comparison.