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Break-Even ACoS: Formula, Examples and Max Bid
Break-even ACoS is the ACoS (advertising cost of sales) at which an ad-driven sale makes zero profit. It equals your profit margin before advertising: break-even ACoS = (sale price − product cost − all Amazon fees) ÷ sale price × 100. If a $29.99 product leaves $12.67 after product cost and fees, its break-even ACoS is 42.2%. Any campaign above that loses money on each sale it drives.
Key takeaways
- Break-even ACoS = profit before ad spend ÷ sale price.
- Your target ACoS should sit below break-even, by the profit margin you want to keep.
- You can turn a target ACoS into a maximum bid: max CPC = price × conversion rate × target ACoS.
- Recalculate when price, cost or fees change, including during holiday peak fees.
The break-even ACoS formula
ACoS is ad spend divided by ad sales. You break even on an ad sale when the ad cost equals the profit you had before ads. So:
Break-even ACoS = profit before advertising ÷ sale price
Profit before advertising is the sale price minus:
- Landed product cost (factory price plus freight, duty and prep)
- Referral fee (15% in most categories, $0.30 minimum)
- FBA fulfillment fee, plus the 3.5% fuel and logistics surcharge in place since 17 April 2026
- Storage per unit
- Inbound shipping and placement costs
- An allowance for returns
Don't subtract ad spend here. That's the number you are solving for.
The related number is break-even ROAS (return on ad spend) = 1 ÷ break-even ACoS.
Worked example
Say you sell a kitchen product for $29.99. It ships as large standard at 14 oz. Inbound and returns figures are example assumptions.
| Line item | Per unit |
|---|---|
| Sale price | $29.99 |
| Landed product cost | −$7.00 |
| Referral fee (15%) | −$4.50 |
| FBA fulfillment fee ($4.60 + 3.5% surcharge) | −$4.76 |
| Storage (0.1 cu ft × $0.78 × 2 months) | −$0.16 |
| Inbound costs (example) | −$0.30 |
| Returns allowance (example) | −$0.60 |
| Profit before advertising | $12.67 |
- Break-even ACoS = $12.67 ÷ $29.99 = 42.2%
- Break-even ROAS = 1 ÷ 0.422 = 2.37
So for every $100 of ad sales, you can spend up to $42.20 on ads before those sales start losing money. Our guide to calculating Amazon profit margin walks through each cost line in detail.
From break-even ACoS to target ACoS
Break-even means zero profit on ad sales. You usually want more than that. Subtract the margin you want to keep:
Target ACoS = break-even ACoS − desired profit margin on ad sales
| Goal | Desired margin on ad sales | Target ACoS (from 42.2% break-even) |
|---|---|---|
| Launch or rank push | 0% or below | 42.2% or higher, for a limited time |
| Growth | 10% | 32.2% |
| Balanced | 15% | 27.2% |
| Profit focus | 25% | 17.2% |
Most products don't run one target forever. A new product might run near break-even for its first weeks, then shift to a growth or profit target once it ranks. See what is a good ACoS for how goals change the answer.
Turn target ACoS into a maximum bid
ACoS depends on three things: what you pay per click, how many clicks turn into orders, and your price. CPC means cost per click. CVR means conversion rate, the share of clicks that become orders. Put them together:
Max CPC = sale price × CVR × target ACoS
Using the example product with a 10% CVR:
| Target ACoS | Max CPC | |
|---|---|---|
| Break-even | 42.2% | $29.99 × 0.10 × 0.422 = $1.27 |
| Balanced target | 27.2% | $29.99 × 0.10 × 0.272 = $0.82 |
If you pay $1.27 per click and 1 in 10 clicks converts, each sale costs $12.70 in ads, which is your whole $12.67 profit. At $0.82 per click, each sale costs $8.20 and you keep about $4.47.
This is the actual CPC you pay, not the bid you enter. Your actual CPC is often a bit below your bid, but placement bid adjustments (for example, a higher bid for top of search) can push it above your base bid. Keep that in mind when you set bids.
Use the right conversion rate
Use the CVR for the specific keyword or target if it has enough data. Many sellers wait for at least 10 to 20 orders before trusting a keyword's CVR. Until then, use the campaign or product average. Ad CVR is often different from your listing's overall unit session percentage in Business Reports, so use ad data for ad bids.
You can run all of this in one place with the free Break-even ACoS & Max Bid Calculator.
How price, deals and fees move break-even ACoS
Break-even ACoS is not fixed. It moves whenever your profit before ads moves.
| Scenario | Profit before ads | Price | Break-even ACoS |
|---|---|---|---|
| Base case | $12.67 | $29.99 | 42.2% |
| $3 coupon (referral fee falls to $4.05) | $10.12 | $26.99 | 37.5% |
| Holiday peak (about +$0.33 fulfillment, +$0.32 storage) | $12.02 | $29.99 | 40.1% |
| Price raised to $32.99 (referral fee $4.95) | $15.22 | $32.99 | 46.1% |
| Landed cost up $1.00 | $11.67 | $29.99 | 38.9% |
Some things to notice:
- Discounts hit hard. A $3 coupon cut break-even by almost 5 points, before counting any coupon fee. Check the current coupon fee in Seller Central and include it.
- Q4 lowers break-even. From 15 October 2026 to 14 January 2027, holiday peak fulfillment fees apply. Amazon says they average about $0.32 more per unit, plus the 3.5% surcharge. Storage also rises to $2.40 per cubic foot for standard-size items from October to December.
- Price increases raise break-even fast. A $3 price increase lifted break-even by almost 4 points, as long as conversion holds.
How to calculate break-even ACoS for your product
- Find your average selling price. In Seller Central, go to Reports > Business Reports > Detail Page Sales and Traffic by Child Item. Divide Ordered Product Sales by Units Ordered for the last 30 days. This catches coupons and deals.
- Get your fees. Use the FBA Revenue Calculator or the Fee Preview report for the referral and fulfillment fee. Multiply the fulfillment fee by 1.035 for the surcharge.
- Add landed cost. Use your real cost per unit for the current inventory, including freight and duty.
- Add storage, inbound and returns. Estimate per unit from your own history.
- Divide. Profit before advertising ÷ average selling price = break-even ACoS.
- Set a target and max CPC. Subtract your desired margin, then use price × CVR × target ACoS for bids.
Common mistakes
Using gross margin
Gross margin (price minus product cost) ignores Amazon fees. On the example product, that would give 76.7% instead of 42.2%, and you would bid far too high.
Subtracting ad spend first
If you subtract your TACoS from profit before calculating break-even, you count ads twice and set targets too low.
Using list price
Your list price may not be what customers pay. Coupons, Subscribe & Save and deals lower the average. Use your real average selling price.
Setting one target for every product
Different products have different margins. A 30% target ACoS can be very profitable on a 50% margin product and a loss on a 25% margin product. Calculate break-even per product, or at least per product group.
Judging every campaign only on ACoS
Break-even ACoS covers ad-attributed sales only. Ads can also lift organic rank and total sales. That's why sellers also watch TACoS. See ACoS vs TACoS for how to read the two together.
Bottom line
Break-even ACoS is your profit margin before advertising. Calculate it per product from your real average selling price and all costs except ads, then subtract the margin you want to keep to get your target ACoS. Turn that target into bids with price × CVR × target ACoS. Recalculate whenever your price, costs or fees change, especially during the holiday peak fee period.
Frequently asked questions
Is break-even ACoS the same as profit margin?
It is the same as your profit margin before advertising costs. Take the sale price, subtract product cost and every Amazon fee except ads, and divide by the sale price. Do not subtract ad spend first, or you will count advertising twice.
Should I ever run campaigns above break-even ACoS?
Sometimes, on purpose and for a limited time. During a product launch or a push to rank for a key search term, many sellers accept an ACoS above break-even because the ad sales can help organic rank. Set a time limit and a budget cap, and judge the result by total sales and TACoS, not ACoS alone.
What is break-even ROAS?
Break-even ROAS is 1 divided by break-even ACoS. If your break-even ACoS is 40%, your break-even ROAS is 2.5, meaning you need $2.50 in ad sales for every $1 of ad spend to break even on those sales.
How often should I recalculate break-even ACoS?
Any time your price, product cost or Amazon fees change. That includes the January fee update, the holiday peak fee period from 15 October to 14 January, a new shipment with a different landed cost, and any coupon or deal that lowers your average selling price.
Does break-even ACoS include storage and returns?
It should. Storage, inbound costs and an allowance for returns are all real costs of selling a unit. Leaving them out gives you a break-even ACoS that is too high, so campaigns that look profitable can actually lose money.
Amazon fees, policies and features change often. Figures here were checked in October 2026; confirm current rates in Seller Central before making pricing or budget decisions. Sotrics is not affiliated with Amazon.