How to calculate the percentage difference between two numbers in Excel
Formula (Excel and Google Sheets)
=ABS(B2-C2)/AVERAGE(B2,C2)Divide the absolute difference by the average of the two: =ABS(B2-C2)/AVERAGE(B2,C2).
- Result on the example
- one result per row in
D2, filled down toD6 - Works in
- Every current version
- Google Sheets
- Same formula
See it work
The formula is already in D2, filled down to D6. Change any input and the result updates, or edit the formula to experiment.
How it works
Percentage difference compares two values when neither is the "before": it divides the gap by their average, so swapping A and B gives the same answer. 120 and 100 differ by 20, and their average is 110, so they are 18.2% apart.
Use percentage change instead when one value is the starting point.
=ABS(B2-C2)/AVERAGE(B2,C2)In Google Sheets
The same formula works in Google Sheets: =ABS(B2-C2)/AVERAGE(B2,C2). We ran it in Google Sheets mode on the same data and it returns the same results.
Other ways to do it
Each one was run on the same example sheet.
| Formula | Result | When to use it |
|---|---|---|
| =(C2-B2)/B2 | -16.7%, 11.1%, 0.0%…Different result | Percentage change from A to B. Use it when A is the baseline. Not symmetric: 120 to 100 is a 16.7% decrease, but 100 to 120 is a 20% increase. |
Common mistakes
- Percentage difference and percentage change are different measures. Pick the one that matches the question, and name it in the report.
- If both values are 0, the formula divides by zero. Guard it with
=IF(AVERAGE(B2,C2)=0,0,ABS(B2-C2)/AVERAGE(B2,C2)).
Try it yourself
Same data, empty answer cell. Your formula is graded instantly, then re-checked on changed data, so a typed-in number won't pass.
Calculate the percentage difference between two numbers
D2, calculate the percentage difference between the two quotes, then fill down to D6.Questions
Which one do I divide by, the bigger or the smaller number?
Neither: percentage difference uses the average of the two. Dividing by one of them is percentage change.
How do I flag quotes that differ by more than 10%?
Compare the result: =ABS(B2-C2)/AVERAGE(B2,C2)>10%.
Checked by running on 2026-10-30: every formula and result on this page was calculated by the Spreadsheet Practice formula engine, in both Excel and Google Sheets modes.