Break-Even ACoS Before Black Friday: Why Your ACoS Target Drops With a Discount
Black Friday is on November 27, 2026, and Cyber Monday on November 30, 2026. On these days you often sell at a discount, but your ACoS target still dates from the time of the normal price. The discount comes entirely out of your margin and leaves much less room for advertising. This article uses an example to show how to recalculate break-even ACoS at the promotion price, and gives you a checklist for the time before the peak.
Break-even ACoS is the share of ad cost at which a sale through ads brings exactly zero profit: margin before ads divided by the selling price. During discount promotions it drops, because the discount comes entirely out of your margin. Example: a €40 price and €12 margin before ads give a 30% break-even ACoS. With a 20% discount, €4 margin remains and only 12.5%. If you do not adjust your ACoS target to the promotion price, you lose money on every ad sale. So recalculate per product before every peak. All numbers here are examples, not Sellantica results.
Why the promotion price moves your ACoS target
Black Friday is on November 27, 2026, and Cyber Monday on November 30, 2026. On these days you often sell at a promotion price. Your ACoS target, however, usually dates from the time of the normal price. That is the trap: the discount does not only reduce your revenue per sale, it comes entirely out of your margin. Product costs and Amazon fees stay roughly the same, so there is much less room left for advertising.
Break-even ACoS is the limit: if your ACoS is above it, every ad sale costs you money. If it is below, something is left over.
Break-even ACoS = margin before ads / selling price x 100
Margin before ads is the price minus product costs and Amazon fees. In the EU, calculate with the price excluding VAT.
Example: 20% discount
An example with a made-up product. All prices are net, meaning excluding VAT. To keep it simple, product costs and Amazon fees stay the same in euros. The numbers are an example, not averages and not results from Sellantica.
| Example | Normal price | 20% discount |
|---|---|---|
| Selling price (net) | €40 | €32 |
| Margin before ads | €12 | €4 |
| Break-even ACoS | 30% | 12.5% |
| Ad cost at 20% ACoS | €8 (profit €4) | €6.40 (loss €2.40) |
At the normal price, a 20% ACoS is clearly profitable. At the promotion price, the same ACoS loses money on every sale, although the campaign looks exactly the same from the outside. If you do not adjust your target, you sell at a loss in the strongest week of the year.
Start with your five best-selling products. For more on the basic calculation, see the article How to Calculate, Understand and Lower Your Amazon ACoS.
Checklist before Black Friday
The following points are general best practice from the sources listed below. They are not a Sellantica service and apply with any tool, or even with a spreadsheet.
- Recalculate break-even ACoS and your maximum bid: per product, using the promotion price. A bid that fits the normal price can be too high at the promotion price.
- Derive daily budgets from your last peak day: Use what was spent on your strongest day last year as a starting point. Set budget rules for the dates instead of switching by hand at midnight. Amazon Ads names a budget increase of 20 to 30% around Black Friday and Cyber Monday as a guideline.
- Scale 3 to 5 days before the peak: Amazon Ads recommends ramping up shortly before. With Black Friday on November 27, that is roughly November 22 to 24.
- Check days of cover: Do not run ads on products that are close to selling out. You pay for clicks that can no longer buy.
- Judge results only 7 days after the click: For Sponsored Products, Amazon counts sales up to 7 days after the click. Numbers from the peak day itself are still incomplete.
- Reset on December 1: Set your targets back to your normal margin. Do not take lessons from the best week of the year into the rest of the year, because discount and demand distort the numbers.
See what is really left for each product
Sellantica shows the product P&L by ASIN, SKU and collection with product costs, Amazon fees and PPC costs. Try it free for 30 days, no credit card required.
Start freeHow Sellantica can help
You can do the calculation yourself in a spreadsheet. With many products it gets tedious, because the numbers come from several reports. Three Sellantica features support you in this phase:
- Product P&L: You see profit and loss by ASIN, SKU and collection with product costs (COGS), Amazon fees and PPC costs. This shows which products still have room at the promotion price. It requires the connection to Amazon via the SP-API.
- Inventory planning: FBA and FBM inventory planning shows days of cover, reorder needs and alerts for upcoming stock-outs. This helps you avoid ads on products that will soon be unavailable.
- Dayparting: Dayparting works with hourly performance (hour heatmap, schedules with approval). You see which hours are worth advertising in and approve the schedules yourself. It requires the Amazon Marketing Stream. More in the article Amazon Dayparting: Advertising at the Right Time.
Frequently asked questions
How do I calculate break-even ACoS?
Divide your margin before ads by the selling price. Margin before ads is the price excluding VAT minus product costs and Amazon fees. Example: €12 margin on a €40 price gives 30%. With a 20% discount, €4 margin remains on a €32 price, which is 12.5%.
When do I start the peak budgets?
Amazon Ads recommends scaling a few days before the peak, 3 to 5 days ahead. With Black Friday on November 27, 2026, that is roughly November 22 to 24. Set your budget rules for those dates in advance instead of switching by hand at midnight.
How long do I wait before judging the results?
For Sponsored Products, Amazon counts sales up to 7 days after the click. Judge Black Friday clicks only from December 4 and Cyber Monday clicks only from December 7, when they are complete.
What do I do after Cyber Monday?
On December 1, set your targets back to your normal margin. Do not carry anything from the best week of the year into your normal settings, because the discount and the high demand distort the numbers.
Which Sellantica features help before Black Friday?
The product P&L by ASIN, SKU and collection shows product costs (COGS), Amazon fees and PPC costs. FBA/FBM inventory planning shows days of cover, reorder needs and stock-out alerts. Dayparting works with hourly performance (hour heatmap, schedules with approval) and requires the Amazon Marketing Stream.
Conclusion: recalculate first, then give budget
A discount is a cost factor for your advertising, not just a price tag. Before Black Friday, recalculate break-even ACoS per product at the promotion price, plan budgets and inventory in advance, and wait until the end of the attribution window before judging. On December 1, set everything back to your normal margin.
Sources and date
All sources were retrieved on 01.11.2026. They are vendor statements and blogs, and the figures in them are unverified. We use them as general best practice, not as evidence of Sellantica results.
- Mirox, "Amazon PPC in Q4 2026" (as of 30.09.2026): break-even calculation, budgets, 7-day rule, reset on December 1. Retrieved on 01.11.2026.
- growwithba.com, "Amazon Q4 PPC Strategy 2026": phase plan, budget rules, pausing before stock-outs. Retrieved on 01.11.2026.
- Amazon Ads, Holiday Advertising Guide 2026 (advertising.amazon.com): three-phase schedule, budget increase of 20 to 30% around Black Friday and Cyber Monday, scaling 3 to 5 days ahead. Retrieved on 01.11.2026.
- daniks.ai, Q4 guide 2026 (vendor blog): dayparting, maximum bid. Retrieved on 01.11.2026.
Last updated: 05.11.2026. Next update: 02.01.2027.