Calculating stacked discounts from the actual checkout total

Apply percentage discounts one after another to the remaining subtotal. For example, 20% off followed by 10% off leaves 72% of the original price, which is a 28% reduction—not 30%.

Check whether a code applies before or after shipping, whether products are excluded, and whether taxes are added afterward. Percentage Calculator can verify the math, but the seller's terms determine the order.

What are the original price and discount rules?