Break-Even ACoS Calculator.
Enter what one unit sells for and what it costs you. The calculator shows the highest ACoS you can run before an ad sale loses money, and the ACoS to aim for if you want to keep a profit margin.
How it is calculated.
Break-even ACoS is what you keep on one unit before advertising, as a share of the sale price. If the ad cost of a sale is exactly that share, you made nothing and lost nothing.
Break-even ACoS = profit before ads ÷ price
Target ACoS = break-even ACoS − the profit margin you want to keep
Break-even ROAS = 1 ÷ break-even ACoS
The referral fee is a percentage of the sale price, so the calculator works it out from the price you enter. Everything else is a dollar amount per unit. "Other costs" is for anything you pay on every unit that is not listed, such as packaging, inserts, storage or an average return allowance.
A worked example.
This is an illustrative example with made-up numbers for a fictional brand. Harbor Kitchen sells a set of storage containers for $40.
| Sale price | $40.00 |
| Product cost, landed | $12.00 |
| Referral fee at 15% of $40 | $6.00 |
| Fulfillment fee | $6.50 |
| Other costs | $1.50 |
| Profit per unit before ads | $14.00 |
$14 divided by $40 is 35%. That is Harbor Kitchen's break-even ACoS: an ad sale that costs $14 in clicks makes nothing. The matching break-even ROAS is 1 ÷ 0.35, or 2.86.
If Harbor Kitchen wants to keep a 10% margin after advertising, its target ACoS is 35% minus 10%, which is 25%. At 25% ACoS the ad cost is $10 per sale and $4 is left over, which is 10% of $40.
What to do with the number.
Use it as the ceiling, not the goal. Break-even tells you where profit hits zero. The number to manage to is the target ACoS, which leaves room for the margin you need. What is a good ACoS on Amazon walks through choosing that target by product stage.
Calculate it per product, not per account. Two products in the same campaign can have very different costs, so one account-wide target will be too loose for one and too tight for the other. ACoS benchmarks by category explains why margin, more than category, sets the ceiling.
Compare it with what your campaigns actually run at. If a campaign sits above break-even, the usual causes are wasted search terms, bids set too high for the conversion rate, or spend in hours that do not convert. How to reduce Amazon ACoS covers the fixes in order, and the hourly ACoS guide shows how to find the hours that push it up.
Check the whole business too. ACoS only looks at ad sales. To see what advertising costs against all your sales, including organic, read ACoS vs TACoS. If you think in ROAS, the Amazon ROAS guide covers the same ground from that side. The ACoS and ROAS calculator and the TACoS calculator do the arithmetic.
Frequently asked questions.
What is break-even ACoS?
Break-even ACoS is the advertising cost of sale at which an ad-driven order makes exactly zero profit. It equals your profit per unit before advertising, divided by the sale price. Run ads below it and each ad sale makes money. Run above it and each ad sale loses money.
How do I calculate break-even ACoS?
Take the sale price and subtract every per-unit cost except advertising: product cost, the Amazon referral fee, the fulfillment fee and anything else you pay per unit. Divide what is left by the sale price. A product that sells for $40 with $26 in costs keeps $14, so its break-even ACoS is 14 divided by 40, or 35%.
Is break-even ACoS the same as profit margin?
Yes, as long as the margin is measured before advertising. Break-even ACoS is your pre-ad profit margin expressed as a share of the sale price. That is why two sellers in the same category can have very different break-even points: their costs are different.
What is the difference between break-even ACoS and target ACoS?
Break-even ACoS is the ceiling, where profit is zero. Target ACoS is the number you actually manage to. It is your break-even ACoS minus the profit margin you want to keep after advertising. With a 35% break-even and a 10% desired margin, the target is 25%.
How do I convert break-even ACoS to ROAS?
ROAS is the inverse of ACoS. Divide 1 by the ACoS written as a decimal. A 35% break-even ACoS is a break-even ROAS of 1 divided by 0.35, or about 2.86. Below that ROAS, ad sales lose money.
Should every campaign run below break-even ACoS?
Not always. Some sellers accept an ACoS above break-even on purpose, for example during a product launch or to defend a ranking, because the ad sale supports organic sales later. The point of knowing the number is that going above it becomes a decision you made, not something that happened without you noticing.