Percentage Difference Calculator
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Calculate the percentage difference between any two values — no starting point needed. Simple, fast, and accurate.
Calculate the percentage difference between any two values — no starting point needed. Simple, fast, and accurate.
Percentage difference measures the relative difference between two values when neither one is considered the "original" or reference point. Instead of dividing by the starting value (as with percentage change), it divides by the average of the two values. This makes it ideal for comparing two figures on equal footing — for example, comparing prices from two different suppliers, or test scores from two different students.
Follow these steps:
Formula:
|A − B| ÷ ((A + B) ÷ 2) × 100
The result is always a positive number since neither value is treated as the reference point.
Example 1
Difference between 80 and 100 = 22.22%
|80 − 100| ÷ ((80 + 100) ÷ 2) × 100 = 20 ÷ 90 × 100
Example 2
Difference between 40 and 60 = 40%
|40 − 60| ÷ ((40 + 60) ÷ 2) × 100 = 20 ÷ 50 × 100
Example 3
Difference between 200 and 150 = 28.57%
|200 − 150| ÷ ((200 + 150) ÷ 2) × 100 = 50 ÷ 175 × 100
What is the difference between percentage difference and percentage change?
Percentage change requires a defined starting value and shows direction (+ or −).
Percentage difference treats both values equally, uses their average as the base, and always returns a positive result.
Why is the result always positive?
Because percentage difference uses the absolute value of the difference (|A − B|),
direction doesn't apply — it simply measures how far apart the two values are.
When should I use percentage difference instead of percentage change?
Use percentage difference when neither value is the "before" or "after" — for example,
comparing two competitors' prices, or two measurements taken at the same time.
What if both values are zero?
If both values are zero the average is zero, making division impossible.
The percentage difference is undefined in this case.