Discount formula
Discount amount = original price × discount percentage ÷ 100.
Final price = original price − discount amount.
Example
If a product costs 80 and the discount is 15%, the discount is 80 × 15 ÷ 100 = 12. The final price is 68.
Multiple discounts
Two discounts are usually applied one after another, not added together. A 20% discount followed by 10% off is not exactly the same as one 30% discount.
Practical tip
Always check whether tax or shipping is added before or after the discount.