Most ACoS arguments start in the wrong place. A seller copies a target from a competitor, a course, or a forum — “keep ACoS under 25%” — and then spends three months forcing campaigns to obey a number that has nothing to do with their own product. For some products 25% is generous. For others it loses money on every single advertised order, quietly, while the dashboard looks disciplined.
There is a correct starting point, and it takes about five minutes: your break-even ACoS — the advertising cost of sale at which an advertised order makes exactly zero profit. Below it, ads make money. Above it, you are paying Amazon to sell your product at a loss. It is not a benchmark. It falls out of your own price, your own cost and your own category fee, which is why nobody else’s number can substitute for it.
What break-even ACoS actually is
Work per unit, and work from contribution.
Contribution before ads is what one unit leaves you after the customer price has been stripped of GST, after Amazon’s marketplace fees, and after everything it costs you to put that product in a box — landed product cost, packaging, the lot. Advertising spends out of this pot and nothing else.
Break-even ACoS is that contribution expressed as a percentage of your net revenue. If a unit contributes ₹321 on net revenue of ₹1,270, your break-even ACoS is about 25%. Spend 25% of revenue on ads to win that sale and you break even. Spend 20% and you keep the difference. Spend 30% and you subsidised the order.
Its mirror image is break-even ROAS: a 25% break-even ACoS is a break-even ROAS of 4. Same fact, two dialects.
The calculation, step by step
- Start with the price the buyer pays, GST included. That is the number on your listing.
- Take the GST out. Revenue you actually earn is the price divided by (1 + GST rate). At 18% GST, a ₹1,499 product nets ₹1,270 before fees.
- Subtract marketplace fees: the referral fee for your category, the closing fee, and the shipping or fulfilment fee per unit. Take the percentages from your own Seller Central fee schedule — they differ by category and change over time, so do not borrow them from an article, including this one.
- Subtract your costs: landed product cost per unit, plus everything else per unit — packaging, a provision for returns, storage.
- What remains is contribution. Divide it by net revenue and you have your break-even ACoS.
If you would rather not do this on paper, our free break-even ACoS calculator runs exactly these steps in your browser — nothing you type is sent to us or stored.
A worked example
Say you sell a product at ₹1,499, GST at 18%, and your numbers look like this:
| Line | Amount |
|---|---|
| Price the buyer pays | ₹1,499 |
| Net revenue after GST out | ₹1,270 |
| Landed product cost | − ₹620 |
| Referral fee (example: 13% of price) | − ₹195 |
| Closing fee | − ₹25 |
| Shipping / fulfilment fee | − ₹79 |
| Packaging, returns provision, storage | − ₹30 |
| Contribution before ads | ₹321 |
Break-even ACoS = 321 ÷ 1,270 = 25.3%. Break-even ROAS ≈ 4.0.
Now the number earns its keep. Set a target ACoS of 20% and each advertised unit spends about ₹254 on ads and leaves you roughly ₹67 profit. Drift to 30% — a number plenty of sellers would call acceptable — and each advertised unit loses about ₹60. Same product, same listing, same campaign structure. The only difference is whether somebody did this five-minute calculation before setting the target.
Four mistakes that make the number lie
Copying a benchmark. A competitor’s sustainable ACoS reflects their price and their cost structure, not yours. A private-label seller at 60% gross margin and a trader at 25% can sell the same product at the same price and have break-even ACoS figures twenty points apart.
Calculating on the gross price. If you divide contribution by the GST-inclusive price, you inflate the denominator and the answer flatters you. ACoS in Seller Central is measured against sales value; your margin lives on net revenue. Mixing the two bases is the most common way this calculation goes wrong.
Forgetting returns. If one unit in ten comes back, and returned units cost you shipping both ways plus refurbishment or write-off, that cost belongs in the per-unit column before you set an ad target. Sellers in apparel and footwear feel this hardest — a contribution that ignores returns is a contribution that does not exist.
Treating a negative contribution as an advertising problem. If step 5 comes out at zero or below, no bid strategy, campaign structure or agency rescues the product. The levers are price, cost and fees, in that order of difficulty — and they have to move before ads spend another rupee. This is why we fix the page and the numbers before we pay for the click: advertising amplifies the unit economics you already have; it does not replace them.
Break-even ACoS is a ceiling, not a target
Two refinements once the ceiling is known.
First, your target should sit below break-even by the profit you actually want, not by a round number. If break-even is 25% and you want ₹100 a unit after ads on ₹1,270 of net revenue, your target is roughly 17%, and now the target is a decision instead of a hope.
Second, watch TACoS alongside it. ACoS only looks at advertised sales. TACoS — total advertising cost of sale — measures ad spend against all revenue, organic included. A healthy account usually sees TACoS fall over time as advertised sales pull organic rank up with them. If ACoS is “fine” but TACoS never moves, your ads are renting every sale you make. Break-even discipline on individual campaigns, TACoS for the health of the whole account: you need both numbers, and the first one takes five minutes.
Do yours before your next budget decision
Every figure above came from the seller’s own account — that is the entire method. Take your best-selling ASIN, pull its real fee lines from Seller Central, and run the five steps. If the answer surprises you, it has already paid for the five minutes.
Run it free, in your browser: Break-even ACoS calculator.
And if you would like a second pair of eyes on the numbers — and on the listing those ads are sending traffic to — that is exactly what our free audit is for. Ads are only half of it; the other half is the listing and ads work itself.
Putting the number to work this week
Knowing the ceiling changes three everyday decisions. Bids: if a keyword converts at your average rate but needs an ACoS above break-even to win volume, the honest options are a better listing, a lower bid that accepts less volume, or walking away — not hoping the algorithm relents. Budgets: a campaign that sits profitably below break-even and runs out of budget by noon is leaving money on the table; a campaign above break-even with an all-day budget is doing the opposite, all day. Assortment: run the calculation across your catalogue, not just your hero ASIN. Most accounts contain a few products whose break-even is so low they should never be advertised directly at all — they earn their place as organic sellers and basket-builders while the ad budget concentrates where contribution can pay for it. Sellers are often surprised to find that a third of their ad spend is defending products that were never able to afford it.
None of this requires new tooling. It requires the five inputs, once, per product — and the discipline to let the answer overrule a benchmark somebody else handed you.
FAQs
What is a good break-even ACoS?
There is no universal good figure — it is whatever your own price, cost and fees produce. A break-even of 35% gives you comfortable room to advertise; a break-even of 12% means ads must be run very tightly or not at all. The useful question is not whether the number is good, but how much room sits between it and your target.
What if my break-even ACoS is very low, like 8–10%?
Then paid advertising on that product is structurally hard. Before increasing budgets, look at price (can it carry a rise?), cost (landed cost, packaging, returns rate) and listing conversion — a better conversion rate means each click is worth more, which is the only honest way a low break-even gets easier to live with.
Does break-even ACoS change over time?
Yes. Referral fee schedules change, shipping fees change, your landed cost changes with suppliers and order volumes, and price changes with competition. Recalculate when any input moves — and at least once a quarter for your main ASINs.
Should every campaign run below break-even ACoS?
Not necessarily. A launch campaign may deliberately run above break-even for a defined period to build rank and reviews — but that should be a budgeted decision with an end date, made with the loss per unit known in advance. Running above break-even by accident, indefinitely, is how accounts bleed.