Is a 20% sale worth running? Here is the volume it needs
A discount takes a percentage off the price and nothing off your cost, so it cuts the money you keep per order — usually by more than the discount looks like. This works out the unit lift the sale must beat: below it the promotion cost you money, above it you are ahead.
Contribution is checked, not revenue: profit per unit is the price minus cost of goods, shipping and every fee. Percentage fees fall with the discount and fixed fees do not, so a 20% discount costs less than 20% of your profit — but it usually costs more than the price cut suggests.
The lift every discount depth needs
The same product at eight depths. The third column is the number to beat: if the sale does not lift units by at least that much, the promotion left you with less money than doing nothing.
| Discount | Kept per order | Units must rise by | Units needed |
|---|
Why the lift is not the discount
Take a US$45 order with US$14 of goods and US$9 of postage on an Etsy Canada shelf. At full price you keep US$17.05 after fees. At 20% off the buyer pays US$36, fees fall to US$4.05, and you keep US$8.95 — a 48% cut in profit for a 20% cut in price. To end the month with the same money you must sell about 1.91 orders for every one you used to sell, a 91% lift. Two things explain the gap: the fees do not fall as fast as the price (fixed fees stay put), and the US$23 of cost does not fall at all. A more forgiving product behaves better — a US$30 item with US$6 of cost on the same shelf needs only a 36% lift at 20% off. On a thin-margin product the same arithmetic turns the sale into a loss on every unit sold, and no volume fixes a negative contribution.
A discount is safe on your high-margin lines and fatal on your thin ones — and most sellers cannot say which is which without doing the arithmetic per item. Run one export free, no signup.
Want the price solved backwards from a target margin instead? The target-margin pricer does that, and a return costs more than the discount.
LAUNCH40 takes 40% off while the first 25 codes last.
Etsy, Amazon, Walmart and TikTok change their fee tables without announcing it, and the Canadian tax deadlines move. I check and send one short email when something real changes. No sequence, no selling you something every Tuesday.
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