Calculate sale price and savings from a percentage discount
Works out the sale price and the amount saved for a given percentage off, and handles stacked discounts, which compound rather than add.
Sale = Original × (1 − d/100) | Savings = Original − Sale
Originallist price before discountddiscount percentageDiscounted Price = Original Price × (1 minus Discount% / 100). For example, a $80 item at 25% off costs $80 × 0.75 = $60.
Original Price = Sale Price / (1 minus Discount% / 100). If an item costs $60 after a 25% discount, the original price was $60 / 0.75 = $80.
Stacked discounts are applied sequentially, not added together. A 20% discount followed by a 10% discount on a $100 item: $100 × 0.80 = $80, then $80 × 0.90 = $72 (not 30% off).