Percentage Difference Calculator
Use this calculator when two numbers should be compared and neither is a starting value. The formula divides the absolute gap by the average of the two numbers, so swapping the inputs does not change the result.
How this is calculated
Take the absolute difference, divide by the mean of the two values, then multiply by 100.
|A − B| / ((A + B) / 2) × 100
- Find the absolute gap. |80 − 100| = 20.
- Find the average. (80 + 100) / 2 = 90.
- Divide and convert to a percent. 20 / 90 × 100 = 22.222…%.
From 80 to 100 is a 25% increase if 80 is the original value. The difference is 22.222% because the base is 90, not 80. Choose change when there is a before and after.
Not the same as
Difference has no starting value and no sign. These tools do.
- Percentage change Change divides by a starting value and reports increase or decrease. Use it for prices, scores, or amounts that moved from A to B. Open percentage change
- X is what percent of Y? That is part over whole. 80 is 80% of 100, which is not the 22.222% difference between them. Open what-percent
Related tools
Percentage-difference questions
22.222…%. The gap is 20 and the average is 90, so 20 / 90 × 100.
25% is the percentage change from 80 to 100. Difference uses the average as the base, which is 90, not 80.
No. Absolute value makes 80 vs 100 the same as 100 vs 80.
When one number is the accepted or true value. Error divides by that accepted value, not by the average.
Not usefully. The average would be zero and the formula would divide by zero.
Yes. |50 − 80| / 65 × 100 = 46.1538…%.