What Is ACoS on Amazon?

Advertising Cost of Sale (ACoS) is the Amazon ad metric that shows what share of your ad-attributed sales got eaten by your ad spend. The formula is simple: ad spend divided by ad-attributed sales, expressed as a percent. It's the most-watched number in any Amazon ad account and one of the most-misused.

ACoS only counts sales Amazon credits to your sponsored campaigns. It does not count the organic sales those ads helped earn by lifting your rank. That gap is why bigger sellers move to Total Advertising Cost of Sale (TACoS) as the headline number and use ACoS underneath as a per-campaign diagnostic.

How ACoS is calculated

ACoS percent equals (ad spend divided by sales from ads), times 100. Sales from ads is the revenue Amazon attributes to your sponsored campaigns in Seller Central. It does not include organic lift driven by ad presence.

Example: you spent $4,000 on Sponsored Products this week. Amazon attributed $16,000 of sales to those ads. ACoS = $4,000 divided by $16,000 = 25 percent. Whether that's profitable depends entirely on your net unit margin after Fulfillment by Amazon (FBA) fees and Cost of Goods Sold (COGS).

Break-even ACoS by category

Break-even ACoS is roughly equal to your net unit margin: (revenue minus COGS minus FBA fees) divided by revenue. As long as ACoS sits below that number, every ad-driven sale is profitable. Rough anchors:

• Apparel at a 35 percent net unit margin: break-even ACoS around 35 percent
• Beauty at a 40 percent net unit margin: break-even ACoS around 40 percent
• Electronics at an 18 percent net unit margin: break-even ACoS around 18 percent
• Commodities at a 12 percent net unit margin: break-even ACoS around 12 percent

The most common mistake

Treating "lowest ACoS" as the goal. The brands that grow fastest spend up to (or near) break-even ACoS on purpose, because high-volume ad traffic drives organic rank, and organic rank compounds month after month. Pure ACoS optimization caps the business at the cheapest, lowest-volume keyword pool. You win the metric and lose the category.

The fix: pair ACoS with TACoS and total Amazon revenue at the brand level. If TACoS is dropping and total revenue is rising, your ads are doing real work even at higher ACoS.

Related Terms

• What is TACoS on Amazon?
• What is an ASIN?
• What is the FBA fee stack?
• What is the Amazon referral fee?
• Sponsored Products vs Brands vs Display

Browse the full ecommerce finance glossary for every metric and money term a DTC operator needs.

Frequently Asked Questions

what does ACoS stand for, and what does it mean?

ACoS stands for Advertising Cost of Sale. It means the share of your ad-attributed sales that got spent on the ads that generated them, calculated as ad spend divided by ad-attributed sales and shown as a percent. A 25 percent ACoS means you spent $25 in ads for every $100 of ad-driven sales.

what's actually a good acos on amazon?

Depends on your category margin. Break-even ACoS is roughly equal to your net unit margin after FBA fees and COGS. Rough anchors: apparel 18 to 35 percent, electronics 8 to 18 percent, beauty 15 to 30 percent. Anything below break-even is profitable. Anything above is paying to grow rank.

acos vs tacos, what's the actual difference?

ACoS only uses ad-attributed sales in the denominator. TACoS uses total sales (ad-attributed plus organic). ACoS measures campaign efficiency. TACoS measures total ad efficiency for the whole brand. TACoS is the better operating metric once you're past launch.

is the lowest acos always the best?

No. Chasing the lowest ACoS caps your growth. A low ACoS usually means you're only bidding on the cheapest, lowest-volume keywords. The brands that scale fastest spend up to break-even ACoS on purpose and let organic rank compound. Optimize for total profit and organic halo, not minimum ACoS.