Stable Numbers
Percentage Difference Calculator
Enter two numbers. See the percentage difference between them. Clear, fair and easy to read.
Need change from an original value instead? Use the percentage change calculator.
How it works
Percentage difference compares two values when neither one is the baseline. It looks at how far apart they are relative to their average. The formula is:
|A − B| ÷ ((|A| + |B|) ÷ 2) × 100
Example. Compare 150 and 180. The absolute difference is 30. The average is (150 + 180) ÷ 2 = 165. 30 ÷ 165 × 100 = 18.18. So the percentage difference is 18.18 percent.
If you do have a clear starting point and a new value, use percentage change instead, since that compares against the original.
When this helps
- Comparing two quotes or prices from different suppliers
- Comparing measurements from two methods or devices
- Checking variation between two samples in a test
- Simple sense checks in reports and dashboards
The result is rounded to two decimals for readability. If you need more precision, adjust the rounding in the code.
Explore more in the percentage tools hub.