How to calculate the percentage difference between two numbers
✓ Verified in LibreOffice 25.8.7.3 ✓ Verified in Google Sheets (2026-08-30)Compare two values symmetrically when neither is the "before" — two prices, two measurements, two vendors.
The formula
| App | Formula | Notes |
|---|---|---|
| Excel (desktop) | =ABS(A2-B2)/((A2+B2)/2) | Symmetric: same answer whichever number comes first. Format as %. |
| Google Sheets | =ABS(A2-B2)/((A2+B2)/2) | Identical. |
| LibreOffice Calc | =ABS(A2-B2)/((A2+B2)/2) | Identical. |
How it works
Percentage DIFFERENCE divides the gap by the average of the two values: |80−100| / 90 ≈ 22.2%, and you get the same answer comparing 100 to 80. That symmetry is the point — use it when neither value is a baseline. When one IS the baseline (old vs new), use percentage CHANGE instead: (new−old)/old, which gives +25% from 80 to 100 but −20% from 100 to 80. Mixing up the two is a common source of "the percentages don't match" arguments.
Verified, not just documented
We ran =ROUND(ABS(A2-B2)/((A2+B2)/2),4) in LibreOffice 25.8.7.3 (headless, with forced recalculation) and it returned 0.2222 — exactly the expected result. We then ran the same formulas in Google Sheets, executed 2026-08-30: a formula-only workbook goes into Google Drive, which converts it to a Sheet and recalculates every formula with Google’s own engine, and comes back out as .xlsx carrying the values Google computed. It returned 0.2222 for the worked example, the same value LibreOffice produced. Both engines’ numbers on this page are executed results. The Excel formula follows Microsoft’s official documented syntax — we do not run desktop Excel.
Functions used
ABS — see full Excel, Google Sheets & LibreOffice compatibility for each.