Enter the original price and a discount to get the final price, the amount saved, and — when a second promotional discount is stacked on top — the true effective discount, which is always less than the two percentages added together.
Formula & methodology
Single discount: final = price × (1 − d). Stacked discounts apply sequentially: final = price × (1 − d₁) × (1 − d₂) — the second percentage acts on the already-reduced price, which is why "20% + extra 10%" is a 28% effective discount, not 30%.
Worked examples
- 80 at 25% off → 80 × 0.75 = 60 (you save 20)
- 100 at 20% + extra 10% → 100 × 0.80 × 0.90 = 72 — effective discount 28%
Limits
Store rounding rules and taxes vary; the displayed cents may differ slightly from a receipt.