Percentage Calculator · Practical guide
Percentage Difference vs. Percentage Change
Two similar-sounding measures that answer different questions — here is how to tell them apart and when to use each.
At a glance
The Core Distinction
Percentage change is directional: it compares a new value to a specific original value, so the order matters. Percentage difference is symmetric: it compares two values without treating either as the starting point, dividing their absolute difference by their average.
Change = ((New − Original) ÷ Original) × 100
Difference = |A − B| ÷ ((A + B) ÷ 2) × 100
Interactive tool
Percentage Calculator
Enter your own values, then compare the result with the examples below.
The Same Two Numbers, Two Different Answers
Compare 80 and 100. The percentage change from 80 to 100 is (20 ÷ 80) × 100 = +25%. The percentage difference between them is 20 ÷ 90 × 100 ≈ 22.22%, because the average of 80 and 100 is 90. Notice the change going the other way — from 100 down to 80 — is −20%, while the difference stays 22.22% no matter which value you list first.
| Values | % Change (first → second) | % Difference |
|---|---|---|
| 80 and 100 | +25% | 22.22% |
| 50 and 80 | +60% | 46.15% |
| 200 and 150 | −25% | 28.57% |
Which One Should You Use?
Use percentage change for anything with a before-and-after: price increases, salary raises, population growth, test score improvement. The % Change tab in the calculator above computes exactly this. Use percentage difference when comparing two independent measurements with no natural starting point — the prices of two competing products, the scores of two teams, or readings from two sensors.
Frequently Asked Questions
Which should I use for price changes over time?
Percentage change, because there is a clear before and after. Divide by the earlier price.
Which should I use to compare two products or teams?
Percentage difference, because neither value is the starting point. It divides by the average, giving the same answer regardless of order.
Can percentage difference be negative?
No. It uses the absolute difference between the two values, so it is always zero or positive. Percentage change can be negative.
Why do the two formulas give different answers?
They divide by different bases: percentage change divides by the original value, while percentage difference divides by the average of the two values.