ACoS (advertising cost of sale) is ad spend divided by the sales those ads drove. TACoS (total advertising cost of sale) is ad spend divided by all sales, including organic. ROAS (return on ad spend) is ad sales divided by ad spend, the inverse of ACoS. Your break-even ACoS equals your profit margin before ads; any ACoS below it makes money on ad-driven sales, and any ACoS above it loses money.
What is ACoS on Amazon?
Amazon Ads defines ACoS as ad spend divided by ad revenue, shown as a percentage:
ACoS = (ad spend ÷ ad sales) × 100
If you spend $50 on ads and those ads produce $200 in attributed sales, your ACoS is 25%. Lower ACoS means each dollar of ad spend brings in more sales.
ACoS only looks at sales Amazon attributes to the ad. It ignores the organic sales that come later because the ad helped your listing rank higher. That is why ACoS alone can mislead you.
What is ROAS?
ROAS = ad sales ÷ ad spend
Using the same example, $200 ÷ $50 = 4, often written as 4x or $4 in sales per $1 spent. ROAS and ACoS measure the same thing from opposite directions. A 25% ACoS is a 4.0 ROAS. A 50% ACoS is a 2.0 ROAS. Amazon's ad console shows both.
What is TACoS?
TACoS = (ad spend ÷ total sales) × 100
Total sales includes organic and ad-driven sales. If you spend $500 on ads in a month and total sales are $5,000, TACoS is 10%.
TACoS shows whether advertising is building the business. If ad spend stays flat and TACoS falls over time, organic sales are growing, which is what you want. If TACoS keeps rising, you are buying more of your sales and the listing is not gaining organic strength.
| Metric | Formula | Answers the question |
|---|---|---|
| ACoS | Ad spend ÷ ad sales | Are my campaigns efficient? |
| ROAS | Ad sales ÷ ad spend | How many sales dollars per ad dollar? |
| TACoS | Ad spend ÷ total sales | Are ads growing the whole business? |
| Break-even ACoS | Profit before ads ÷ price | What is the most I can pay per sale? |
How do you calculate break-even ACoS?
Break-even ACoS is your profit margin before advertising. Amazon Ads puts it simply: keep ad spend lower than your profit margin, or you spend more on ads than you earn.
Break-even ACoS = (sale price − all costs except ads) ÷ sale price
Worked example
Take a $30 product. Using the numbers from our FBA fees example:
- Referral fee: $4.50
- FBA fulfillment fee with 3.5% surcharge (est.): $4.97
- Storage and inbound placement (est.): $0.46
- Inbound shipping: $0.50
- Landed product cost: $8.00
Total costs before ads: $18.43. Profit before ads: $30.00 − $18.43 = $11.57.
Break-even ACoS = $11.57 ÷ $30.00 = 38.6%.
So on this product:
- At 25% ACoS, each ad sale costs $7.50 in ads and you keep $4.07.
- At 38.6% ACoS, you break even on ad-driven sales.
- At 50% ACoS, each ad sale costs $15.00 and you lose $3.43 on it.
Plug your own product into the FBA profit calculator to get your break-even number.
What is a good ACoS?
There is no single good ACoS. It depends on your margin and your goal.
- Launch: running above break-even is normal for a new product with no reviews. You are buying sales history and ranking. Set a time limit and a budget cap, such as 60 to 90 days.
- Growth: run near break-even to gain market share while organic rank improves. Watch TACoS to confirm organic sales are rising.
- Profit: run well below break-even on proven keywords and cut wasteful spend.
A 45% ACoS can be fine on a product with a 60% margin. A 20% ACoS can lose money on a product with a 15% margin. Always compare ACoS to your own break-even, not to someone else's number.
If your ad spend keeps climbing but profit does not, we can review your campaigns against your real break-even.
Book a Free Strategy Call →How should you structure Amazon PPC campaigns?
Clean structure makes the numbers readable. A simple setup for one product:
- Auto campaign: lets Amazon find search terms. Use it for discovery with a modest budget.
- Manual exact match: your best converting keywords, with tight bids based on break-even ACoS.
- Manual phrase or broad match: to find variations of your main keywords.
- Product targeting: ads on competitor listings or complementary products.
Every week or two, move search terms that convert from auto and broad into exact match, and add terms that spend without converting as negative keywords. This loop is where most of the efficiency comes from.
Which ad types can you use?
- Sponsored Products: ads for single listings in search results and on product pages. Available to Professional sellers.
- Sponsored Brands: headline ads with your logo and several products. Requires Brand Registry.
- Sponsored Display: retargeting and product targeting on and off Amazon, also for brand-registered sellers.
Which numbers should you track each week?
A short weekly scorecard keeps the focus on profit, not just ad metrics:
- ACoS by campaign, compared to your break-even.
- TACoS for the whole product, to see whether organic sales are growing.
- Conversion rate (orders divided by clicks), which tells you if the listing is doing its job.
- Total profit after ads, the number that actually matters.
If ACoS improves but total profit falls, you may have cut too much. If TACoS climbs month after month, ads are carrying the product and organic rank is not keeping up.
Example: reading a search term report
Say your break-even ACoS is 38.6% and your auto campaign shows these search terms after two weeks:
| Search term | Clicks | Spend | Sales | ACoS | Action |
|---|---|---|---|---|---|
| Term A | 85 | $68 | $300 | 22.7% | Move to exact match, raise bid slightly |
| Term B | 60 | $51 | $120 | 42.5% | Keep, lower bid a little |
| Term C | 110 | $77 | $0 | — | Add as negative exact |
| Term D | 12 | $9 | $0 | — | Wait for more data |
Term A is profitable and deserves its own exact-match ad group. Term B is slightly above break-even, so a small bid cut may bring it into profit. Term C has spent enough with no sales to be cut. Term D has too few clicks to judge.
Repeat this every week or two and your campaigns get cheaper over time without cutting good traffic.
How do you lower ACoS without losing sales?
- Improve conversion first. Better main image, clearer title, stronger bullets, and more reviews raise the share of clicks that buy. That lowers ACoS at every bid.
- Cut wasted spend. Negative keywords for irrelevant terms are the fastest win in most accounts.
- Bid by placement. If top-of-search converts better for your product, bid up there and down elsewhere.
- Adjust by time. If sales drop overnight, reduce budget during those hours using schedules.
Common ACoS mistakes
- Judging too early. A keyword with 20 clicks and no sales may not be bad yet; one with 100 clicks and no sales usually is.
- Ignoring the listing. Poor images, a weak title, or few reviews lower conversion. Lower conversion means higher ACoS, no matter how you bid.
- Bidding the same everywhere. Top-of-search placements often convert differently. Use placement adjustments.
- Chasing ACoS alone. Cutting every ad that is not profitable can shrink total sales and organic rank. Watch TACoS and total profit too.
Putting it together
Know your break-even ACoS before you spend a dollar. Use ACoS to manage campaigns, TACoS to judge whether ads are growing the business, and ROAS when you want to compare channels. If you are still planning your launch budget, see what it costs to start FBA in 2026. If you would rather have a team manage campaigns, our Amazon FBA automation service includes PPC management within your account.