ACOS compares advertising spend with ad-attributed sales. TACOS compares advertising spend with total sales. ACOS focuses on advertising efficiency; TACOS helps show how advertising spend relates to the wider Amazon business.
What is ACOS?
Advertising cost of sales, or ACOS, measures how much advertising spend was used to produce ad-attributed sales during the selected reporting period.
If ACOS rises, it does not automatically mean the campaigns are failing. The change could reflect higher click costs, weaker conversion, broader targeting, a deliberate launch strategy, pricing changes, increased competition, or the selected attribution period.
What is TACOS?
Total advertising cost of sales, commonly called TACOS, compares advertising spend with total Amazon sales rather than only ad-attributed sales.
TACOS can help you evaluate whether advertising investment is growing faster or slower than the account’s total sales. Because total sales include organic and ad-attributed revenue, TACOS adds a wider commercial view—but it still does not explain causation by itself.
How to interpret the two metrics together
ACOS rises while TACOS remains stable
Advertising may have become less efficient while total sales remained strong enough to absorb the change. Investigate traffic quality, conversion, click costs, and the purpose of the affected campaigns before reacting.
ACOS improves while TACOS rises
Ad-attributed efficiency may be improving even while advertising consumes a larger share of total sales. This can happen when organic sales weaken, spend expands, or the sales mix changes.
Both metrics improve
This is directionally positive, but still check total contribution, unit economics, inventory, price, and sales volume. A low ratio attached to very little revenue is not automatically a healthy growth outcome.
Neither metric equals profit
ACOS and TACOS are cost-to-sales ratios. They do not include every cost required to calculate profit. A useful review should also consider:
- Gross margin and contribution margin
- Amazon fees, promotions, coupons, and returns
- Cost of goods, freight, and storage
- Pricing and conversion-rate changes
- Organic sales and branded demand
- Inventory availability and the product’s lifecycle stage
A better operating question
Instead of asking whether ACOS or TACOS is “good,” ask whether the current level is appropriate for the product economics and campaign objective. A launch, defense campaign, mature bestseller, clearance product, and high-margin niche item may require different decisions.