Amazon PPC / ACoS
Amazon Break-Even ACoS by Category: The Formula, Lookup Table, and Bid Cap Guide
Your break-even ACoS is the maximum you can spend on ads and still cover all costs. It changes by category, and using it as a bid cap is the single most reliable way to stop losing money on Sponsored Products.
Published September 10, 2026 · Updated September 10, 2026 · Illustrative education, not accounting or tax advice.
1. The formula
Break-even ACoS is a function of your contribution margin per sale. The formula is the same regardless of category or fee structure:
In plain English: if you keep $7 of contribution margin on a $20 sale, your break-even ACoS is 35%. Any ad spend above 35% of the sale price puts the ad-driven order underwater.
2. Quick lookup table by category
This is a starting point, not a substitute for your own numbers. Contribution margin varies widely within a category depending on price point, brand, and fees.
| Category | Typical contribution margin | Break-even ACoS | Target ACoS (≈½ break-even) |
|---|---|---|---|
| Beauty & personal care | 55–70% | 55–70% | 28–35% |
| Home & kitchen | 45–65% | 45–65% | 22–32% |
| Pet supplies | 45–60% | 45–60% | 22–30% |
| Apparel (mid-tier) | 35–50% | 35–50% | 17–25% |
| Toys & games | 30–45% | 30–45% | 15–22% |
| Sports & outdoors | 30–45% | 30–45% | 15–22% |
| Supplements & grocery | 20–35% | 20–35% | 10–17% |
| Books | 15–25% | 15–25% | 8–12% |
| Low-ticket ($5–10) impulse | 10–20% | 10–20% | 5–10% |
| High-ticket ($100+) | 50–70% | 50–70% | 25–35% |
Pattern: the lower your contribution margin, the higher your break-even ACoS sits, and the less room you have for advertising. Low-margin categories require either higher prices, lower product cost, or smaller ad budgets to be viable.
3. Worked example: $25 supplement on FBA
Consider a $25 supplement, FBA, in the Supplements category.
If your actual ACoS on Sponsored Products for this product is 35%, every ad-driven order contributes 10 percentage points of headroom toward overhead and net profit. If your ACoS is 50%, every ad-driven order loses $1.25 before overhead. The 45% threshold is the line.
4. Why "5x ROAS" can still lose money
Many sellers chase a round number like "5x ROAS" without grounding it in margin. ROAS is just the inverse of ACoS: 5x ROAS = 20% ACoS. Whether 20% ACoS is good depends entirely on your contribution margin:
- If your contribution margin is 50%, then 20% ACoS leaves 30% for overhead and profit. Healthy.
- If your contribution margin is 25%, then 20% ACoS leaves only 5%. Almost no margin for overhead.
- If your contribution margin is 15%, then 20% ACoS exceeds break-even. You are losing money on every ad-driven order.
The discipline is: figure out break-even ACoS first, then decide what target ROAS makes sense relative to it. Round numbers are fine for shorthand; they are dangerous as strategy.
5. Using break-even ACoS as your Sponsored Products bid cap
Once you know your break-even ACoS, use it directly as your default bid cap in Sponsored Products:
- Open Sponsored Products > Campaigns > select a campaign.
- Edit the bid. Set the default bid just below your break-even ACoS (e.g., break-even 45% → bid 42%).
- For top-converting keywords, raise the bid by 5–10 percentage points. These keywords have a higher effective margin because they convert at higher rates.
- For poor-converting keywords, lower the bid toward break-even or pause.
This is not an aggressive growth strategy. It is a discipline strategy. Use it for the first 60–90 days of a campaign, then add incremental budget only after the campaign has demonstrated profitable orders.
6. When it makes sense to bid above break-even
Bidding above break-even ACoS is not always wrong. Three legitimate reasons to do it:
- Lifetime value beyond the first purchase. If your repeat purchase rate is 30% and average order value is stable, your effective contribution margin per first order is higher than the per-order margin suggests.
- Launch phase. You are willing to lose money on the first 30 orders to capture organic ranking signals. After 30 days, drop bids back to break-even.
- Defending a ranked position. If your category is highly competitive and dropping below break-even would cost you page-1 placement, the ranking signal may be worth the short-term loss.
If none of those apply, treat break-even ACoS as your hard ceiling. The most common way small Amazon sellers lose money is bidding above break-even "to get more impressions" without a clear reason.
7. Plug your numbers into the calculator
The Amazon ACoS calculator takes your ad spend, attributed sales, and total sales and returns ACoS, TACoS, and ROAS. The break-even ROAS calculator takes your revenue and non-ad costs and returns the multiplier you need. Run both side by side.
If your actual ACoS is consistently above break-even ACoS, the issue is either your bidding strategy, your conversion rate, or your product economics. The calculator tells you which lever to pull.
8. Frequently asked questions
What is a good break-even ACoS for Amazon?
1 divided by your contribution margin per sale. A 30% contribution margin gives 33% break-even ACoS. A 60% margin gives 60%.
What is a good ACoS for Amazon in 2026?
There is no universal answer. Use your contribution margin to derive your break-even ACoS, then set a target ACoS at roughly half that.
How do I calculate break-even ACoS for FBA?
Subtract referral + FBA fees + product cost + packaging + per-order variable costs from the sale price. That is your contribution margin. Divide by sale price.
Does break-even ACoS change by category?
Yes. Higher-margin categories (beauty, home, pet) have higher break-even ceilings. Lower-margin categories (supplements, books, low-ticket impulse) have lower ceilings and tighter ad budgets.
Should I bid above my break-even ACoS?
Only if LTV, launch phase, or ranking defense justifies it. Otherwise, treat break-even as your hard ceiling.
Difference between break-even ACoS and target ACoS?
Break-even is the maximum before you lose money. Target is what you aim for to leave room for overhead and net profit. Target is always lower.
Can break-even ACoS be my Sponsored Products bid cap?
Yes. Set default bids just below break-even. Raise for proven keywords, lower or pause for poor ones.
How often should I recalculate?
At least once per quarter, or whenever Amazon fees, FBA rates, product cost, or shipping costs change.
9. Keep these limits visible
- Amazon referral and FBA fees change. Reconfirm in Seller Central before treating the lookup table as exact.
- ACoS is a campaign-level metric; use TACoS for store-level health and ROAS for individual keyword economics.
- This guide is not investment advice, tax advice, or a guarantee of any specific Amazon seller outcome.
- Taxes, currency conversion, and inventory holding costs sit outside this model.
Try it on your numbers
Open the Amazon ACoS calculator →See also the break-even ROAS calculator for the marketing-side version. Read the methodology page for how we model contribution.
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