Break-Even ACoS Calculator
Break-even ACoS is the advertising cost of sale at which an advertised order contributes exactly zero profit: every dollar of margin left after product cost and Amazon fees has been spent buying the click that produced the sale. It equals your pre-ad profit divided by your selling price. This calculator derives that ceiling from your price, landed cost, referral fee, FBA fulfillment fee, and other per-unit costs, then works out the lower target ACoS you need to hit if the SKU is to keep a chosen net margin. Enter your own numbers below; the fields load with a worked example already filled in.
Calculate your advertising ceiling
How the break-even ACoS calculation works
ACoS is a ratio of spend to revenue, so the ceiling is found by asking how much of the selling price is still unspent by the time the order is ready to ship:
- Referral fee = selling price × referral rate. Amazon charges this percentage of the total sales price on every order, so it scales with price rather than sitting as a fixed amount.
- Pre-ad profit per unit = selling price − landed product cost − referral fee − FBA fulfillment fee − other per-unit costs. This is the money the SKU has available to spend on advertising before it starts losing money.
- Break-even ACoS = pre-ad profit ÷ selling price. Expressed as a percentage, this is the ratio at which advertising spend exactly consumes the remaining margin.
- Advertising budget per unit at break-even = pre-ad profit stated in dollars. Some sellers find the dollar figure easier to hold in mind than the ratio, and it is the number that connects directly to a cost-per-click ceiling.
- Target profit per unit = selling price × target net margin. If you want to keep 10% of a $24.99 price, that is $2.50 that advertising must not touch.
- Target ACoS = (pre-ad profit − target profit) ÷ selling price. This is the ratio to actually manage campaigns against, and it always sits below break-even by exactly the margin you asked to keep.
The relationship is worth stating plainly, because it is the whole point of the exercise: break-even ACoS is a ceiling, not a goal. An advertised order at break-even pays for the product, the fees, and the clicks, and leaves you nothing. Every point of ACoS below the ceiling is profit; every point above it is money spent out of your own pocket to make a sale. That can be a rational decision, but it has to be a decision, with a budget attached and a date on which it stops.
Note also what this ceiling does not account for. ACoS only sees ad-attributed sales. If advertising is buying rank and that rank produces organic orders, the true cost of advertising to the business is lower than any single campaign's ACoS suggests. The metric for that view is TACoS, total advertising cost of sale, which divides ad spend by total sales rather than by attributed sales. A SKU running at 30% ACoS with a 9% TACoS is advertising efficiently in the round, even though each attributed order looks marginal. Track both, use ACoS for bid decisions and TACoS for portfolio decisions, and read the definitions side by side on the key metrics reference.
One more caution about inputs. Enter the fees for the price you are actually charging today, not the price you launched at. Referral fees scale with price, so a discount lowers the fee and the pre-ad profit at the same time, but not in the same proportion. A coupon or a deal cuts your ceiling faster than it cuts your price, which is why campaigns that were comfortably profitable at full price quietly go underwater during a promotion.
Worked example: a $24.99 kitchen SKU
These are the values the calculator loads with, so you can see the method and the widget agree. Figures are illustrative.
- Selling price $24.99, landed cost $8.20, referral rate 15%, FBA fulfillment fee $6.10, other costs $0.00, target net margin 10%.
- Referral fee: $24.99 × 0.15 = $3.75.
- Pre-ad profit: $24.99 − $8.20 − $3.75 − $6.10 − $0.00 = $6.94 per unit.
- Break-even ACoS: $6.94 ÷ $24.99 = 27.8%. That is also the advertising budget per unit at break-even, stated as $6.94.
- Target profit at a 10% margin: $24.99 × 0.10 = $2.50.
- Target ACoS: ($6.94 − $2.50) ÷ $24.99 = 17.8%. Manage bids to that figure and treat 27.8% as the line you do not cross without a reason.
The gap between 17.8% and 27.8% is exactly the 10% net margin you asked to keep, which is a useful sanity check: raise the target margin by five points and the target ACoS drops by five points. To convert either figure into an actual bid, carry it into the PPC max bid calculator along with your conversion rate.
Frequently asked questions
What is a good break-even ACoS?
There is no universal figure, because break-even ACoS is simply your pre-ad margin restated as a percentage. A healthy private-label SKU usually lands somewhere between 20% and 35%. Below 15% the product has almost no room to buy traffic, and above 40% you are typically selling something with an unusually light fee load or an unusually high price.
Is it ever correct to advertise above break-even ACoS?
Yes, but only as a deliberate, budgeted decision with an end date. Launch periods, rank defense against a competitor, and clearing aged inventory before a long-term storage fee lands are all defensible reasons to run at a loss per advertised order. The failure mode is drifting above break-even by accident and calling it a growth investment.
What is the difference between ACoS and TACoS?
ACoS is ad spend divided by ad-attributed sales, so it judges the advertising in isolation. TACoS is ad spend divided by total sales, organic included, so it judges what advertising costs the business as a whole. The break-even figure on this page is an ACoS ceiling. TACoS is the number to watch over months to see whether ad spend is buying durable organic rank.
Why does the ACoS in my advertising console differ from this ceiling?
The console reports what your campaigns actually spent against attributed revenue over a chosen window, using an attribution period that keeps updating for days after a click. This page reports what your unit economics can afford. The two only meet when reported ACoS is compared against the ceiling for the same SKU at its current price.
Should I set my target ACoS equal to the break-even number?
No. Targeting break-even means planning for zero profit on every advertised order and relying entirely on organic sales to fund the business. Set the target below break-even by whatever net margin you need, which is exactly what the target ACoS row calculates, then treat break-even as the hard ceiling you only cross on purpose.
Sources
- Amazon Seller Central: referral fee schedule, FBA fulfillment fees, and advertising campaign reports (primary source for your exact fees and your reported ACoS).
- Seller Signal analysis. All example figures above are illustrative planning values, not current published rates.