Explanation
How Discount Calculator works
When announcing a price reduction for goods, section 11 PAngV generally requires the lowest total price of the previous 30 days as the reference; the rule contains details and exceptions. The calculator determines amounts but does not assess whether the German rule applies or whether advertising is lawful.
Discount calculations are particularly relevant during seasonal promotions such as Black Friday, Cyber Monday or end-of-season sales. Retailers frequently use crossed-out prices showing the previous price. The actual savings can only be verified when the final price is correctly calculated against the real prior price (not the RRP). Equally important: the difference between final price and discount percentage — 50% off sounds impressive, but on a 10 EUR item you only save 5 EUR.
For typical shopping questions, the most relevant figures are final price, discount amount, original price and the actual discount percentage.
Economically, a discount is a price reduction granted as a percentage of the original selling price. In retail, distinctions are made between functional discounts (for wholesalers), volume discounts, loyalty discounts and time-limited promotional discounts.
Section 11 PAngV generally requires the lowest total price of the previous 30 days when a reduction for goods is announced. Whether the rule or an exception applies is not a calculation question.
R = P x r / 100The discount amount R is the original price P times the discount rate r divided by 100.
E = P - RThe final price E is the original price minus the discount amount.
P = E / (1 - r / 100)When the final price and discount are known, divide by the remaining price fraction.
r = (P - E) / P x 100Original price minus final price gives the savings. Relative to the original price, this yields the discount percentage.
E = P x (1 - r1/100) x (1 - r2/100)Two sequentially applied discounts are calculated as the product of the respective remaining factors, not as the sum of percentages.