# Percentage Difference Calculator

URL: https://speedycalculator.com/calculators/math/percentage-difference/
Last updated: 2026-10-25

> The percentage difference calculator compares two values when neither is the reference, by dividing their difference by their average. It is symmetric, so swapping the values gives the same answer.

## Inputs

- Value A
- Value B

## Results

- Percentage difference
- Change from A to B

## Formula

```
% difference = |a − b| ÷ ((a + b) ÷ 2) × 100
```

## Explanation

Use percentage difference to compare two prices, measurements or products where neither is the “original”.

### How to use the Percentage Difference Calculator

- **Value A**
- **Value B**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Take the absolute difference and divide by the mean of the two values.

### Inputs explained

FieldWhat to enterValue AA numberValue BA number

### What each result means

- **Percentage difference** = abs([Value A] - [Value B])÷(([Value A] + [Value B])÷2) × 100
- **Change from A to B** = ([Value B] - [Value A])÷[Value A] × 100

### Example values

How the main result changes when **Value A** changes and everything else stays at the example values above:

Value APercentage difference (%)6085.7143905012022.2222150018018.181824046.1538

## Worked example

Inputs — Value A: 120; Value B: 150.

Results — **Percentage difference = 22.2222 %**; Change from A to B = 25 %.

## FAQ

**How is this different from percentage change?**
Percentage change uses the original as the base; percentage difference uses the average.

**Why do I get different answers from other tools?**
Some sites mean percentage change when they say difference.

**What formula does the Percentage Difference Calculator use?**
% difference = |a − b| ÷ ((a + b) ÷ 2) × 100.