Amazon advertising metrics
Amazon ACoS Calculator
Calculate Amazon advertising cost of sales and ROAS from ad spend and ad-attributed sales, then compare the result with optional target and break-even ACoS thresholds.
Campaign inputs
Use figures from the same Amazon Ads reporting period and attribution view.
Use ad-attributed sales, not total Amazon revenue.
Add optional ACoS comparisons
Your campaign target. Values above 100% are supported.
Enter your own threshold based on product economics.
Amazon ACoS
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Enter campaign ad spend and ad-attributed sales to calculate ACoS.
Campaign metrics breakdown
- Ad Spend
- $0.00
- Ad-Attributed Sales
- $0.00
- Amazon ACoS
- —
- ROAS
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- Ad Spend per $100 of Attributed Sales
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What is Amazon ACoS?
Advertising cost of sales, or ACoS, measures ad spend as a percentage of ad-attributed sales. It answers a narrow but useful question: how many advertising dollars were spent for each $100 of sales attributed to the campaign?
Amazon ACoS formula
ACoS = Ad Spend / Ad-Attributed Sales x 100
ROAS = Ad-Attributed Sales / Ad Spend
For positive values: ROAS = 1 / ACoS (decimal)
ACoS vs ROAS
ACoS and ROAS view the same spend-to-sales relationship from opposite directions. ACoS is a percentage of sales consumed by ad spend. ROAS is a multiplier showing attributed sales per ad dollar. For example, 25% ACoS corresponds to 4.00x ROAS.
What does a high ACoS mean?
A higher ACoS means more ad spend was required for each dollar of attributed sales. ACoS can exceed 100%; that means ad spend exceeded attributed sales during the measured period. It is not capped by the calculator.
What does a low ACoS mean?
A lower ACoS means less ad spend relative to attributed sales, but it does not prove that a product is profitable. Product costs, Amazon fees, fulfillment, returns, and campaign goals still matter.
What is Target ACoS?
Target ACoS is a seller-selected campaign benchmark. A useful target depends on product economics, break-even ACoS, margin, growth goals, and whether the campaign prioritizes efficiency, launch visibility, or another objective. There is no universal target that fits every seller.
What is Break-Even ACoS?
Break-Even ACoS is the ad-spend percentage where the contribution available for advertising is fully used. In this calculator it is an optional value supplied by you. The calculator does not derive it from product costs in Task 6.
Worked example
Example inputs: ad spend $50.00, ad-attributed sales $200.00, target ACoS 20%, and Break-Even ACoS 30%.
- Amazon ACoS: 25.00%
- ROAS: 4.00x
- Ad spend per $100 of attributed sales: $25.00
- Target comparison: Above target, +5.00 percentage points
- Break-even comparison: Below break-even
- Maximum break-even ad spend: $60.00
- Estimated contribution remaining after ads: $10.00
How Amazon sellers can use ACoS
Use ACoS to compare campaigns on a consistent reporting basis, monitor movement against a chosen target, and see whether spend is above or below a seller-provided break-even threshold. Review it alongside conversion, sales volume, product margin, and campaign objectives rather than treating it as a complete profit metric.
Limitations
ACoS only compares advertising spend with ad-attributed sales. It does not automatically include Amazon referral fees, FBA fulfillment fees, storage fees, COGS, inbound freight, shipping, returns, taxes, or other seller costs. A campaign can have a low ACoS while the underlying product is still unprofitable.
Use the Amazon Break-Even ACoS Calculator or Amazon Profit Calculator when you need product economics. This calculator does not replace Amazon Ads reports or seller accounting records.
Frequently asked questions
What is Amazon ACoS?
Amazon ACoS is ad spend divided by ad-attributed sales, expressed as a percentage.
How do I calculate Amazon ACoS?
Divide campaign ad spend by ad-attributed sales and multiply the result by 100. The two figures should cover the same reporting period and attribution view.
What is a good Amazon ACoS?
There is no universal good ACoS. A useful threshold depends on break-even economics, margin, campaign objective, growth goals, and how sales are attributed.
Is lower ACoS always better?
No. Lower ACoS indicates lower spend relative to attributed sales, but may accompany lower volume or conflict with launch and growth objectives. It also does not include product economics.
What is the difference between ACoS and ROAS?
ACoS divides ad spend by attributed sales. ROAS divides attributed sales by ad spend. With positive spend and sales, they are reciprocal views of the same relationship.
Can Amazon ACoS be over 100%?
Yes. ACoS above 100% means ad spend was greater than attributed sales for the figures entered.
What is Target ACoS?
It is a campaign benchmark selected by the seller based on economics and campaign goals. The optional comparison reports the difference in percentage points.
What is Break-Even ACoS?
It is the ACoS threshold at which available contribution is consumed by advertising. Task 6 accepts your value; it does not calculate the threshold from costs.
Why is my Amazon ACoS high?
Possible causes include higher click costs, low conversion, pricing changes, campaign targeting, attribution timing, or a reporting period with spend but limited attributed sales. Investigate the underlying campaign data before drawing a conclusion.
Does ACoS include Amazon fees?
No. Standard ACoS compares ad spend with attributed sales. Referral, FBA, storage, and other selling costs are outside this formula.
Should I use ACoS or ROAS?
Both can be useful. ACoS makes ad spend as a share of sales easy to compare with margin thresholds, while ROAS shows sales generated per ad dollar.