ACoS vs TACoS vs ROAS: what's a good ACoS on Amazon?
Three ratios, one question: are your ads making money? Here's what each one answers, and the math to set a target that fits your margins.
Short answer
ACoS is ad spend divided by ad-attributed sales. ROAS is the same ratio flipped: ad sales divided by ad spend. TACoS is ad spend divided by total sales, ads and organic together. There's no universal good ACoS. A good ACoS is below your break-even ACoS, which equals your profit margin before ad spend. Use ACoS to judge campaigns and keywords, and TACoS to see whether ads are growing the whole business or just buying sales you'd have made anyway.
On this page
The three formulas
All three use the same ad spend. They just divide it by different things.
| Metric | Formula | What it answers |
|---|---|---|
| ACoS (advertising cost of sales) | Ad spend ÷ ad-attributed sales | Is this campaign or keyword efficient? |
| ROAS (return on ad spend) | Ad-attributed sales ÷ ad spend | Same question, upside down. ROAS = 1 ÷ ACoS |
| TACoS (total advertising cost of sales) | Ad spend ÷ total sales | How much of the whole business runs on ads? |
ACoS and ROAS live in the ads console. TACoS needs total sales from Seller Central, which is why so few sellers check it.
A worked example
One product, one month. These numbers are an example, not a benchmark:
| Line | Amount |
|---|---|
| Ad spend | $3,000 |
| Ad-attributed sales | $10,000 |
| Total sales (ads + organic) | $30,000 |
| ACoS | $3,000 ÷ $10,000 = 30% |
| ROAS | $10,000 ÷ $3,000 = 3.33 |
| TACoS | $3,000 ÷ $30,000 = 10% |
Same month, three numbers. A 30% ACoS can look scary. A 10% TACoS says ads are a small slice of a business that mostly sells on its own. Neither tells you whether you made money. For that you need your margin.
What is a good ACoS?
The one that's below your break-even ACoS. Break-even ACoS is your profit margin before ad spend: price minus Amazon fees, cost of goods and inbound shipping, divided by price. Above it, every ad-driven sale loses money.
| Line (example) | Per unit |
|---|---|
| Price | $30.00 |
| Amazon fees (referral + FBA) | −$10.00 |
| Cost of goods and shipping in | −$8.00 |
| Profit before ads | $12.00 |
| Break-even ACoS | $12 ÷ $30 = 40% |
So 35% ACoS is fine on this product and a loss on a product with a 25% margin. That's why “a good ACoS is 25%” advice doesn't survive contact with your P&L. Profit per ASIN shows where each input lives.
From break-even to a target
Break-even is the line you don't cross. Your target ACoS depends on what the ads are for:
| Goal | Target ACoS | Example (40% break-even) |
|---|---|---|
| Profit on every ad sale | Break-even minus the profit you want to keep | Keep $4 a unit: ($12 − $4) ÷ $30 = 27% |
| Launch or rank a new product | At or above break-even, on purpose, with an end date | 40–50% for a set number of weeks |
| Defend your brand terms | Low, because those shoppers already want you | Well under break-even |
The launch row is the only one where losing money on ads is the plan. Write the end date down. “Temporarily unprofitable” has a way of becoming a lifestyle.
When ACoS misleads you
ACoS is a ratio of two numbers Amazon reports, so it inherits their quirks:
- The attribution window. Amazon credits a Sponsored Products sale to an ad if it happens within a set window after the click: 7 days for sellers and 14 days for vendors at the time of writing. Amazon sets these windows and can change them.
- Recent days are unfinished. Sales keep arriving for days after a click, so the last few days' ACoS looks worse than it will end up. Judge complete weeks.
- Attributed isn't caused. Some shoppers who clicked would have bought anyway, especially on your own brand terms. A low brand-term ACoS can be partly organic sales wearing an ad costume.
- Other products count. Amazon's attributed sales can include other items from your catalog bought after the click, not only the advertised one.
None of this makes ACoS useless. It makes it a campaign-level tool, not a verdict on the business.
TACoS: the whole-business view
TACoS asks a better question over time: are ads helping the business grow, or just renting sales?
| What you see over a few months | What it usually means |
|---|---|
| TACoS falling, total sales rising | Ads are lifting organic sales. The good kind of addiction |
| TACoS flat, total sales rising | Ads and organic growing together |
| TACoS rising, total sales flat | Ads are replacing organic sales, not adding to them |
| TACoS rising, total sales falling | Find out why before you spend more |
To calculate it, take total sales from Seller Central's Business Reports (the Sales and Traffic report) for the same dates and marketplace as your ad spend. Keep each marketplace separate: add dollars and pounds into one TACoS and you get a number that means nothing.
Where ROAS fits
ROAS is ACoS flipped, so it never disagrees with it. It's handy if you think in Google or Meta terms, or if your team reports “dollars back per dollar spent.” Break-even ROAS is 1 ÷ break-even ACoS: a 40% break-even ACoS is a break-even ROAS of 2.5. Pick one of the two for your reports so nobody has to do division in a meeting.
Get all three without the spreadsheet
The annoying part of TACoS is joining two systems. Connected to both through an MCP server like WavyCloud, your AI app can do the join:
Ask your AI
For each ASIN, show the last 30 days of ad spend, ad sales, total sales, ACoS, TACoS and break-even ACoS from my product costs. Flag ASINs where ACoS is above break-even.
Frequently asked questions
What is a good ACoS on Amazon?
There's no universal number. A good ACoS is below your break-even ACoS for that product, which is your profit margin before ad spend. If you keep $12 of a $30 sale before ads, break-even ACoS is 40%, and your target sits below that unless you're deliberately paying for a launch.
What's the difference between ACoS and TACoS?
ACoS divides ad spend by sales Amazon attributes to your ads. TACoS divides the same ad spend by total sales, including organic. ACoS judges how efficient a campaign is; TACoS shows how dependent the whole business is on ads.
How do I calculate break-even ACoS?
Subtract Amazon fees, cost of goods and inbound shipping from the price to get profit before ads, then divide by the price. A $30 product with $12 profit before ads has a break-even ACoS of 40%.
Is a lower ACoS always better?
No. A very low ACoS can mean you're only bidding on terms that would convert anyway and missing profitable sales. The goal is the most profit, not the smallest ratio, so aim for a target below break-even rather than as low as possible.
Is ROAS the same as ACoS?
They use the same two numbers. ROAS is ad sales divided by ad spend, and ACoS is ad spend divided by ad sales, so ROAS equals 1 divided by ACoS. A 25% ACoS is a ROAS of 4.