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:

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:

• Percentage Change Calculator
• Percentage Points Calculator
• All Calculators

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.