How Much Can You Discount on Black Friday Without Losing Money?
Most store owners pick a Black Friday discount the way they pick a lottery number: 20% feels respectable, 30% feels brave, 50% feels desperate. The number that actually matters is different for every product, and it is usually lower than you think.
Here is how to work out your own ceiling in about ten minutes, with a worked example you can copy.
Why "my margin is 70%" is the wrong number
If a $60 product costs you $18 to make or buy, your gross margin is 70%. That sounds like room for a 50% sale. It is not, because gross margin ignores everything else that happens to a Black Friday order:
- Shipping and packaging you pay on every order.
- Payment fees: a percentage plus a fixed fee (for example 2.9% + $0.30 on many card processors; check your own rates, and add marketplace fees into the percentage if you sell on one).
- Ad cost per order: during Black Friday and Cyber Monday you often pay more to get the same click. Use your blended cost per order, not your best day.
- Returns: the refund itself, return shipping, and the share of returned items you cannot resell.
Discounts only shrink the price. Every cost above stays the same. So each dollar you give away comes straight out of profit.
The formula
For one product:
profit per order = sale price × (1 − return rate − fee %)
− product cost × (1 − return rate × resale %)
− shipping − fixed fee
− return rate × return shipping
− ad cost per order
Your break-even price is the sale price where this equals $0. Your maximum safe discount is the sale price where profit equals the minimum you are willing to earn per order. Anything deeper loses money, or earns so little that it is not worth the work.
A worked example
A small store sells a product at $60. Its numbers:
| Input | Value |
|---|---|
| Product cost | $18 |
| Shipping and packaging | $6 |
| Ad cost per order | $15 |
| Payment fee | 2.9% + $0.30 |
| Return rate | 8% (80% of returns resellable) |
| Return shipping | $6 |
| Minimum profit you want | $5 per order |
At full price you keep about $14.83 per order. Now watch what discounts do:
| Discount | Sale price | Profit per order | Orders needed to match one full-price order's profit |
|---|---|---|---|
| 0% | $60.00 | $14.83 | 1.0× |
| 10% | $54.00 | $9.49 | 1.6× |
| 20% | $48.00 | $4.14 | 3.6× |
| 25% | $45.00 | $1.47 | 10.1× |
| 30% | $42.00 | −$1.21 | never |
| 40% | $36.00 | −$6.55 | never |
The results:
- Maximum safe discount (keeping $5 profit): about 18%, a sale price of roughly $48.97.
- Break-even discount: about 27.7%, a sale price of roughly $43.35.
- A "respectable" 20% off already earns less than your $5 minimum. A 30% sale loses money on every order, so the harder it sells, the worse the day gets.
That last column is the one people skip. At 20% off you need about 3.6 times as many orders just to earn what one full-price order earned. Black Friday traffic does not reliably give you that.
The three traps that break the math
- Stacked codes. A 20% sitewide sale plus a 15% welcome code plus free shipping is not "20%". Take the combined effect and compare it with your ceiling. Test a cart with every code before you launch.
- Ad costs that move. If your cost per order rises from $15 to $20 during the sale, the example above loses roughly another $5 on every order. Re-run the numbers with the Black Friday cost, not the October cost.
- One discount for the whole catalog. Your ceiling differs per product. A $9 item with a $3 ad cost has a very different answer from the $60 item above. Discount your high-margin products harder and keep the thin ones at or near full price.
What to do when the ceiling is low
If your safe discount is under 15%, a big percentage-off sale is probably the wrong tool. Alternatives that protect profit:
- Bundles: sell two items for a price that is "20% off" the pair only when the second item is high-margin.
- Free shipping above a threshold, set above your average order value.
- Early access for past customers: no extra ad cost, because you already paid for them once.
Run your own numbers
I built a free calculator that does exactly this math: enter your price, cost, shipping, fees, ad cost per order, returns, and the minimum profit you need. It shows your maximum safe discount, your break-even discount, and a profit table from 0% to 50% off. It runs in your browser, with no signup, and nothing is stored.
Free: Black Friday discount calculator
Black Friday is on November 27 this year and Cyber Monday on November 30, so you have a few weeks. Running the numbers for your five best-selling products before you set any discount takes about ten minutes.
These are estimates, not financial advice. Check your own payment fees, returns and ad costs.
Optional: the BFCM 2026 Profit-Safe Kit ($12)
If you want the whole plan and not just the math: a 50-product profit spreadsheet, a discount-stacking checker, a dated 30-day task plan, and ready-to-paste emails and SMS. Secure checkout by Stripe; full refund within 7 days if it isn’t useful.
Disclosure: I made it, together with an AI agent.