Percentage Difference Calculator Guide: Compare Two Values Accurately
What Is Percentage Difference?
Percentage difference expresses the relative difference between two numbers as a percentage of their average value.
It’s most useful when you want to know how much two values differ proportionally rather than in absolute terms.
Formula:
Percentage Difference = (|A - B| ÷ ((A + B) ÷ 2)) × 100
Example 1: Comparing Prices
You see two laptops:
- Laptop A: $800
- Laptop B: $1,000
|A - B| = 200 Average = (800 + 1000) ÷ 2 = 900 Percentage Difference = (200 ÷ 900) × 100 = 22.22%
Result: The price difference between the two laptops is 22.22%.
Use our percentage difference calculator to confirm instantly.
Example 2: Comparing Test Results
Two students score:
- Student A: 84
- Student B: 90
Difference = 6
Average = 87
Percentage difference = (6 ÷ 87) × 100 = 6.9%
Their scores differ by about 7%, which indicates similar performance.
Example 3: Scientific Measurement Comparison
Two measurements of the same object:
- Trial 1: 9.81 m/s²
- Trial 2: 9.65 m/s²
Difference = 0.16
Average = 9.73
Percentage difference = (0.16 ÷ 9.73) × 100 = 1.64%
A low percentage difference shows consistent results — ideal for scientific experiments.
Percentage Difference vs. Percentage Change
These two are often confused but measure different things:
| Concept | Formula | Reference Point | Use Case |
|---|---|---|---|
| Percentage Change | ((New - Old) ÷ Old) × 100 | Initial value | Growth or decline |
| Percentage Difference | ( | A - B | ÷ Average) × 100 |
If you’re tracking growth over time, use the percentage change calculator.
If you’re comparing two separate numbers, use the percentage difference calculator.
Practical Uses
- Finance: Compare company profits or prices across years
- Science: Evaluate experimental consistency
- Data analysis: Compare two datasets
- Everyday math: Price differences, grades, or percentages
Try It Yourself
Enter your values in our percentage difference calculator to get an instant and accurate result.
You can also explore:
In short:
Percentage difference tells you how two numbers relate proportionally. It’s a small concept with huge value in analysis, finance, and everyday life.
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