ACoS calculator
ACoS is advertising cost of sales: ad spend divided by the sales those ads drove. It is just ROAS upside down, and the Amazon world runs on it. Solve it any way and see the ROAS it equals and the break-even ACoS your margin allows.
Using typical funnel assumptions, to show that the metric above can’t tell you if you’re winning. Your real numbers live in the full calculator.
Drop in one product and the Target ROAS calculator works your whole P&L backwards to the number that actually decides it, free, no signup.
What is ACoS?
ACoS, advertising cost of sales, is the share of your ad-driven revenue that you spent on those ads. It is the metric the Amazon world runs on, and it is simply ROAS turned upside down: a 25% ACoS is the same as a 4x ROAS.
How to calculate ACoS
What is a good ACoS? Your break-even ACoS
There is no universal good ACoS; there is your break-even ACoS, and it equals your profit margin. If a product carries a 30% margin, a 30% ACoS breaks even on the ad-driven sale. Below it you profit, above it you lose money on that unit, unless you are spending deliberately to rank or launch.
ACoS measures ad spend against ad-driven sales only. TACoS (total ACoS) measures ad spend against total sales, including organic. A falling TACoS as you spend is the sign that ads are lifting organic rank, the real goal.
How to lower ACoS
- Tighten targeting and add negative keywords so spend stops landing on terms that do not convert.
- Improve the listing's conversion rate (images, title, reviews, price); a higher CVR lowers ACoS without touching bids.
- Adjust bids toward the keywords that actually sell, away from the ones that only spend.
- Raise margin, which lifts the break-even ACoS you can afford. For the full unit economics, use the Amazon FBA calculator.
The operator’s playbook
How a paid-media operator reads this number, not a glossary definition.
Break-even ACoS equals your margin+
You break even when ACoS equals your gross margin: a 40% margin means a 40% break-even ACoS. Below it you profit, above it you pay to lose money. Target ACoS sits below break-even by however much profit you want to keep.
ACoS vs TACoS+
ACoS only looks at ad-attributed sales. TACoS (total ACoS) divides ad spend by total sales, including organic. Falling TACoS as you spend is the real sign ads are lifting the whole listing, not just renting sales.
Frequently asked questions
How do you calculate ACoS?
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Ad spend divided by ad sales, times 100. $300 of spend driving $1,200 of sales is a 25% ACoS. This tool also solves for the spend or sales behind a target ACoS.
What is a good ACoS?
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Anything below your gross margin is profitable; the gap is your profit. There is no universal number: a 35% ACoS is great at a 50% margin and a loss at 25%.
Is ACoS the same as ROAS?
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They are inverses. ROAS = 100 / ACoS. A 25% ACoS is a 4x ROAS. Amazon sellers use ACoS; Meta and Google use ROAS.
What is the difference between ACoS and TACoS?
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ACoS measures ad spend against ad-driven sales only. TACoS measures it against total sales, including organic. A falling TACoS as you spend means ads are lifting organic rank.
What is break-even ACoS?
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The ACoS that equals your profit margin, where the ad-driven sale makes zero profit. Below it you profit; above it you lose money on that unit unless you are spending to rank.
How do I lower my ACoS?
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Tighten targeting, add negative keywords, improve the listing's conversion rate, and bid toward the keywords that actually sell. Raising margin also lifts the ACoS you can afford.
Built by Yehonatan Tav, paid media for ecommerce brands spending $50k to $500k a month. Figures are illustrative; run the logic on your own numbers.