Percent Difference Calculator

What is Percent Difference?

Percent difference measures the relative difference between two values as a percentage of their average. Unlike percent change, percent difference treats both values equally without considering one as the reference point. This calculation is essential for comparing two numbers when neither is considered the standard or original value.

Percent Difference Formula

Percent Difference = (Value 1 - Value 2) ÷ [(Value 1 + Value 2) ÷ 2] × 100%

Where:

• |Value 1 - Value 2| is the absolute difference
• (Value 1 + Value 2) ÷ 2 is the average of the two values

How to Calculate Percent Difference

1. Find the absolute difference between the two values
2. Calculate the average of the two values
3. Divide the difference by the average
4. Multiply by 100 to get the percentage

Examples of Percent Difference Calculations

Scientific Measurements

Value 1: 85 grams
Value 2: 95 grams
Percent Difference = |85 - 95| ÷ [(85 + 95) ÷ 2] × 100 = 11.1%

Price Comparison

Store A Price: $45
Store B Price: $55
Percent Difference = |45 - 55| ÷ [(45 + 55) ÷ 2] × 100 = 20%

When to Use Percent Difference

Use percent difference when:

• Comparing two measurements
• Neither value is considered "correct" or "original"
• Looking for relative variations
• Analyzing experimental results
• Comparing prices or rates

FAQ About Percent Difference

What's the difference between percent difference and percent change?

Percent difference compares two values equally using their average, while percent change uses one value as the reference point.

Can percent difference be negative?

No, percent difference is always positive because it uses absolute value in the calculation.

Why use the average in the denominator?

Using the average provides a fair comparison when neither value is considered the standard or original value.