Amazon Break-Even ACoS Calculator
ACoS has no idea what your product costs. Work out the line where a sale earns you nothing, and you'll usually find it sits lower than the target you've been running.
What's left of a sale
Per unit, before a cent goes to advertising. All Amazon US FBA figures.
Turn it into a target
Points of the selling price left after ad spend. Break-even leaves nothing for overheads this page never sees, so don't aim at zero.
Add the conversion rate of the ads and you get the most a click can cost at that target. Use ad purchases divided by ad clicks from your search term report, not the listing's session conversion rate.
A ceiling on what a click can cost, not a base bid. Placement multipliers and dynamic bidding compound on top of the base bid. The bid calculator works that through.
Runs entirely in your browser. Nothing you type gets sent anywhere. Connect your account free and the fees come from your own settlement data instead.
Why ACoS on its own lies to you
A 30% ACoS is either excellent or ruinous and the number itself will never tell you which. It compares ad spend to ad sales and stops there. It knows nothing about Amazon's cut, the fulfillment fee, what you paid the factory, or the units coming back. Two sellers running the identical ACoS can be on opposite sides of profitable.
On the default numbers that's $13.71 left out of a $35 sale, so break-even lands at 39.2%. Run a 45% ACoS against it and every order costs you about two dollars. Nothing in Seller Central puts those two numbers next to each other, which is why accounts drift past the line for months without anyone noticing.
Two things worth saying plainly
Break-even isn't a goal
It's the floor. A sale at break-even covers its own direct costs and contributes nothing to the rent, the salaries, the software, or you. Pick a target with real daylight under the line.
Over the line can be correct
Launches and ranking campaigns are supposed to run above break-even. You're buying rank and reviews, not profit. The difference between that and drifting is whether you decided to.
Where each number comes from
Two Seller Central reports carry almost all of it.
FBA Fee Preview
Per-SKU estimated referral and fulfillment fees. The fastest way to stop guessing at the two Amazon charges.
Settlement report
What actually settled rather than what was estimated, including the fees on refunded orders. This is the honest version.
Your own COGS
The one number Amazon can't tell you. Landed cost: factory price, freight, duty and tariffs, per unit.
Return rate
Returns divided by units ordered over the same window. Apparel runs far higher than most categories, so use yours.
One trap when you pull the fees: a rolled-up fee total usually already contains the referral fee. Enter that total as your fulfillment fee and then put a referral percentage in as well and you've charged yourself twice. Split the components out instead — and don't pool them by dropping the total into fulfillment and setting referral to $0, because the two behave differently on a refund. Amazon gives the referral fee back less an administration fee, and keeps the fulfillment fee. Pooling them charges you full retention on both and understates what's left.
What this can't see
Per-unit contribution is the right frame, but it's a frame. Five things sit outside it and each one can flip a decision.
Your overheads
Contribution isn't profit. Rent, salaries, software, agency fees and your own time all come out of it afterwards. A SKU at break-even ACoS is losing money at the company level.
Repeat purchases
If a consumable sells five times a year to the same buyer, the first order's margin isn't its whole value. Judging replenishables on one order's contribution systematically underbids them.
Cross-SKU attribution
Ad cost lands on the ASIN you advertised, but attributed sales include other SKUs the shopper bought. Applying one SKU's margin to all of it can justify spend that isn't earned.
Organic halo
ACoS only counts the sales the ad got credit for. Ads that lift rank produce organic orders it never sees, which is why TACoS exists and why launches deliberately sit over the line.
Costs that move
Q4 storage rates, tariff changes, a freight spike, an FBA fee revision, a factory price break at volume. A break-even ACoS is a snapshot, not a standing instruction. Recompute it each quarter.
One SKU at a time, from memory
This page needs you to know your own numbers and do one product at a time. Connect Amazon Ads and Seller Central and your AI assistant works the same math across your whole catalogue from settled fee data, then tells you which SKUs are already running past their line.
- Ask which ASINs are advertising above break-even and by how much.
- Turn a target into a bid ceiling per keyword.
- Get bid changes applied through AI once you approve them.
- Check inventory next to ad performance before scaling a winner.
Frequently Asked Questions
Break-even ACoS is the advertising cost of sale at which a sale contributes nothing. It equals your contribution margin expressed as a share of the selling price: everything left after Amazon's referral fee, fulfillment, your cost of goods, and a returns allowance. Spend exactly that share on ads and the sale washes its face. Spend more and the sale is bought at a loss, which can still be the right call on a launch, but should be a decision rather than a surprise.
Take the selling price, subtract the referral fee, the FBA fulfillment fee, your landed cost of goods, and any other per-unit costs. That is contribution on a sale you keep. Then account for refunds: a refunded unit gives the revenue back but you keep paying the fulfillment fee and the cost of goods, and Amazon keeps a refund administration fee. Divide the expected contribution by the selling price and you have break-even ACoS.
However much contribution margin you want the sale to keep. If break-even is 39% and you want the sale to hold 15 points of contribution after ads, target 24%. The two numbers share a denominator, the selling price, so you subtract percentage points directly. Bear in mind that break-even leaves nothing for overheads this calculator never sees, so a target at or just under break-even is not a profitable business, it is a sale that covers its own direct costs.
More than most people expect, because a refund is not a cancelled sale. The customer gets the money back, but the FBA fulfillment fee stays paid, the unit may come back unsellable, and Amazon retains a refund administration fee, usually the lesser of five dollars or twenty percent of the referral fee. On a thirty-five dollar product with a five percent return rate that is roughly two points of break-even ACoS. This calculator assumes returned units are not resellable and nothing is reimbursed, which is the conservative end.
Fifteen percent is the common case in many Amazon US categories, but it is an example, not your number. Rates vary by category, several categories are tiered by price, and some carry a per-item minimum. Check your own category in Amazon's fee schedule, and if your category has a minimum or a tier that a flat percentage misrepresents, switch the field to dollars and enter the actual per-unit fee from a fee preview or settlement report.
They are the same fact stated two ways. ROAS is ad sales divided by ad spend, ACoS is ad spend divided by ad sales, so break-even ROAS is one divided by break-even ACoS. A 40% break-even ACoS is a 2.5 break-even ROAS. Use whichever your team already speaks; just do not mix the two in one conversation, which is how people end up agreeing on a target they each understood differently.
Close, but reconcile the revenue basis first. Amazon's attributed ad sales are recorded gross at the time of order, exclude tax, and are not reduced when the order is later refunded, so this calculator uses the gross selling price as its denominator to match. Where it drifts: coupons and promotions reduce what the shopper actually pays, attributed sales include units beyond the advertised SKU, and attribution windows differ by campaign type. Reconcile those before treating the threshold as a number you can paste into a report.
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