ACoS (advertising cost of sales) is the percentage of ad-attributed sales you spend on Amazon advertising. To calculate it, divide ad spend by the sales Amazon attributes to your ads and multiply by 100: $360.00 of spend that brings in $1,200.00 of attributed sales is a 30% ACoS. ROAS is the same ratio turned around, sales divided by spend. Enter your own numbers to get both.
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ACoS compares what you spent on ads with the sales Amazon attributes to those ads over the same period. ROAS uses the same two numbers the other way around.
ACoS = ad spend ÷ attributed sales × 100
ROAS = attributed sales ÷ ad spend
A Sponsored Products campaign spent $360.00 last month, and Amazon attributed $1,200.00 of sales to it.
| Metric | Calculation | Result |
|---|---|---|
| ACoS | $360.00 ÷ $1,200.00 × 100 | 30% |
| ROAS | $1,200.00 ÷ $360.00 | 3.33 |
| Ad cost per $1.00 of sales | $360.00 ÷ $1,200.00 | $0.30 |
The campaign spends $0.30 on ads for every $1.00 of attributed sales. Whether that makes money depends on the product’s margin, which is what the result needs to be compared with.
There is no ACoS that is good for every product. ACoS ignores price, cost of goods and Amazon fees, so the same figure can be a healthy profit on one product and a loss on another. To judge it, compare it with the product’s break-even ACoS: its profit per unit before advertising, as a percentage of the selling price.
| Your ACoS is | What it means for ad-attributed sales |
|---|---|
| Below break-even | Each sale is profitable after its ad cost. |
| At break-even | Ads pay for themselves, with no profit left on those sales. |
| Above break-even | Each sale loses money. Sellers sometimes accept this during a launch or a push for ranking, but it should be a deliberate choice. |
For example, a product priced at $25.00 that makes $10.00 per unit before advertising has a break-even ACoS of 40%. At the 30% ACoS above, it keeps 10% of each attributed sale as profit. Work out your own products with the break-even ACoS calculator, which also turns a target margin into a target ACoS.
ROAS (return on ad spend) divides attributed sales by ad spend, so it is the inverse of ACoS: ROAS = 100 ÷ ACoS, and ACoS = 100 ÷ ROAS. A lower ACoS and a higher ROAS describe the same improvement.
| ACoS | ROAS |
|---|---|
| 10% | 10.00 |
| 20% | 5.00 |
| 25% | 4.00 |
| 30% | 3.33 |
| 40% | 2.50 |
| 50% | 2.00 |
| 100% | 1.00 |
A 100% ACoS, or a ROAS of 1.00, means ad spend equals the sales it brought in, so those sales lose money once cost of goods and fees are counted.
Amazon attributes Sponsored Products sales over 7 days after a click for sellers and 14 days for vendors, and Sponsored Brands and Sponsored Display over 14 days. ACoS from different ad types or windows measures different things. The window also means the last few days of any report are incomplete: sales can still arrive for recent clicks, so recent ACoS often comes down as the data settles.
The same ACoS can be profitable on a product with a wide margin and lose money on one with a thin margin. Set targets per product, or per group of products with similar margins, from each one’s break-even ACoS.
A keyword with no orders has no ACoS at all, and its first order can make it look excellent. Let a new campaign or keyword collect enough clicks to have had a fair chance to convert, judged against your usual conversion rate, before raising or cutting bids.
TACoS divides the same ad spend by total revenue, organic sales included, so it is usually lower. A 30% ACoS and a 7.5% TACoS can describe the same campaigns in the same month. Compare ACoS with ACoS and TACoS with TACoS.
One that sits below the product’s break-even ACoS by enough to leave the margin you want. Margins differ too much between products for one number to suit everyone. The break-even ACoS calculator gives you a limit and a target for each product.
Divide 100 by ACoS. A 25% ACoS is a ROAS of 4.00, and a ROAS of 5.00 is a 20% ACoS.
No. ACoS counts only sales Amazon attributes to your ads within the attribution window. To measure ad spend against all sales, organic included, use the TACoS calculator.
Amazon can attribute a sale to an ad click for up to 7 or 14 days after the click, depending on the ad type and account. Spend for recent days is already counted, but some of the sales from those clicks haven’t arrived yet, so ACoS for that period often falls as the data settles.
A calculator works for a spot check. Agentic Sellar connects Amazon Ads and Seller Central to Claude, ChatGPT and other AI tools, so you can ask for every campaign’s spend, attributed sales and ACoS for a date range, then compare each one with its product’s break-even ACoS. Agentic Sellar doesn’t bid on its own: if your AI tool proposes a bid change, it needs a write scope and your confirmation before anything reaches Amazon Ads.