How to Calculate Percentage Difference (With Calculator)

Ever wondered how to compare two numbers and see how different they are—in percentage % terms?

Whether you’re comparing prices, test scores, profits, or website traffic, knowing the percentage difference helps you measure change clearly.

This article explains how to calculate percentage difference, gives you a formula you can copy and paste, and includes a calculator and infographic to make it super simple.

Use the calculator below to quickly find the percentage % difference between two numbers

🙋 What Is Percentage Difference?

Percentage difference shows you how far apart two values are—as a percentage of their average.

It’s useful for comparing values that don’t have a clear starting or ending point, like:

• Comparing two salaries
• Measuring price changes across stores
• Evaluating sales from two different months
• Comparing two student test scores

🧪 Formula for Percentage Difference

Here’s the standard formula:

Percentage Difference = (|Value 1 - Value 2| ÷ Average of the Two Values) × 100

Where:

• |Value 1 - Value 2| is the absolute difference between the two numbers
• The average is (Value 1 + Value 2) ÷ 2

Example

Let’s compare two numbers: 150 and 100

Difference = |150 - 100| = 50  
Average = (150 + 100) ÷ 2 = 125  
Percentage Difference = (50 ÷ 125) × 100 = 40%

✅ The percentage difference is 40%

📌 When to Use It

Use percentage difference when:

• There’s no fixed start or end value
• You want to compare two independent values
• You want to see how far apart two values are in a fair way

🚀 Pro Tip

If you’re comparing a new value to an old value (like price changes or growth), you might want to use percentage increase/decrease instead. But for balanced comparisons, percentage difference is your best friend

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