Percent Off vs Sale Price
A percentage discount reduces the original price:
Sale Price = Original Price × (1 − Discount% / 100)
Example: 25% off a $80 item:
Sale = 80 × (1 − 0.25) = 80 × 0.75 = $60
You save 80 − 60 = $20.
Stacked Discounts
Retailers rarely add percentages — 20% + 10% is not 30% off.
Usually each discount applies sequentially:
Price after first = Original × (1 − 20%)
Price after second = First result × (1 − 10%)
Combined equivalent discount ≈ 1 − (0.8 × 0.9) = 28% off — close to but not 30%.
Dollar-Off vs Percent-Off
| Type | Best when |
|---|---|
| $10 off | Predictable savings on small carts |
| 10% off | Scales with basket size — better on large purchases |
Compare effective discount: $15 off $100 = 15%; 10% off on $200 = $20 off.
How to Use This Discount Calculator
Enter original price and discount (percent or amount). See final price and amount saved. Use it while shopping to avoid misleading "was/now" psychology.