Start from an example:
Price and discounts
$
%
%
Applied after the first discount. 0 if none.For sellers (optional)
$
Product plus shipping. Leave 0 to skip margin.Sales tax, platform fees and shipping charges are not included.
How the discount is calculated
Stacked discounts
price × (1 − discount) × (1 − coupon)A coupon on top of a sale applies to the already reduced price, so 25% + 10% is 32.5% off, not 35%.
Margin after discount
(final price − cost) ÷ final priceThe share of the sale price you keep. It falls faster than the price does.
Extra sales needed
profit before ÷ profit after − 1How many more units you must sell at the lower price to earn the same total profit.
Frequently asked questions
How do I calculate 25% off?
Multiply the price by 0.75. $80 × 0.75 = $60.
Is 20% off then 10% off the same as 30% off?
No. It is 28% off, because the 10% applies to the reduced price.
How big a discount can I afford?
Keep the final price above your cost plus fees. Check the margin after discount and the extra sales you would need.