How to calculate the discount percentage from two prices
✓ Verified in LibreOffice 25.8.7.3Original price and sale price in hand — what percent off is that?
The formula
| App | Formula | Notes |
|---|---|---|
| Excel | =1-B2/A2 | A2=original, B2=sale price. Format as a percentage. |
| Google Sheets | =1-B2/A2 | Identical. |
| LibreOffice Calc | =1-B2/A2 | Identical. |
How it works
The sale price is B2/A2 of the original (60/80 = 75%), so the discount is what's missing from 100%: 25% off. It's algebraically the same as (A2-B2)/A2 — dollars saved over original — use whichever reads better to you. The reverse direction (applying a known discount to get a price) is the calculate-a-discounted-price recipe; and note a 25% discount is NOT undone by a 25% increase — that asymmetry lives in the percentage-change recipe.
Verified, not just documented
We ran =1-B2/A2 in LibreOffice 25.8.7.3 (headless, with forced recalculation) and it returned 0.25 — exactly the expected result. Every formula here is confirmed by actually executing it.