ACoS vs TACoS: What's the Difference?
ACoS (advertising cost of sales) is ad spend divided by the sales your ads produced. TACoS (total advertising cost of sales) is ad spend divided by your total revenue, paid and organic. ACoS tells you how efficient your ads are. TACoS tells you how dependent your business is on ads. A healthy account usually has a TACoS that holds steady or falls while total revenue grows.
The formulas
| Metric | Formula | What it answers |
|---|---|---|
| ACoS | Ad spend ÷ ad sales × 100 | How much do I pay in ads for each $1 of ad sales? |
| TACoS | Ad spend ÷ total sales × 100 | What share of all my revenue goes to advertising? |
| ROAS | Ad sales ÷ ad spend | How many dollars of ad sales does $1 of spend bring? (ROAS = 1 ÷ ACoS) |
Example: one US account I manage spent $116,258.78 on ads in September 2026, got $311,577.64 in ad sales and $506,376.38 in total revenue. ACoS = 37.3%, TACoS = 23.0%, ROAS = 2.68. (See the case study.)
Why you need both
ACoS only looks at sales Amazon attributes to your ads. It ignores the organic sales that advertising helps create: better ranking from ad-driven sales velocity, repeat buyers, and shoppers who saw an ad and later bought without clicking one.
- ACoS falling, TACoS falling: ads are getting more efficient and organic sales are growing. The ideal case.
- ACoS rising, TACoS falling: often fine. You may be investing in ranking or new keywords, and it is paying off in organic sales.
- ACoS falling, TACoS rising: ads look efficient, but organic sales are shrinking. Check rankings, reviews and competitors.
- Both rising: spend is growing faster than sales. Time for an audit.
What is a good ACoS?
There is no universal number. The useful benchmark is your break-even ACoS: your profit margin before advertising. If a product sells for $40 and you keep $12 after product cost, Amazon fees and shipping, your break-even ACoS is 30%. Below 30% the ad sales are profitable. Above it they lose money, which can still be a deliberate choice during a launch.
Set targets per product, not per account. A hero product you are pushing up the rankings can run above break-even, and a mature product should run well below it.
What is a good TACoS?
Again, it depends on margin and stage. What matters most is the direction: a TACoS that stays flat or falls while revenue grows means advertising is building the business. In the US supplements case study, TACoS dropped from 53.7% to 10.0% in 30 days with ad sales unchanged, because the account had been paying for clicks that never converted.
Frequently asked questions
ACoS is ad spend divided by ad sales. TACoS is ad spend divided by total sales, including organic. ACoS measures ad efficiency, and TACoS measures how much of your whole business depends on advertising.
Use both. Set ACoS targets per product from your break-even margin, and watch TACoS over time to confirm advertising is growing total sales rather than only buying the sales it reports.
Break-even ACoS equals your profit margin before advertising: selling price minus product cost, Amazon fees and shipping, divided by selling price.
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