TACoS vs ACOS, side by side.

Worked example

Period A: $3,000 ad spend, $9,000 ad sales, $15,000 total. ACOS 33.3%, TACoS 20%, organic $6,000. Period B: the same $3,000 spend, $12,000 ad sales, $30,000 total. ACOS 25%, TACoS 10%, organic $18,000. TACoS fell 10 points and organic sales tripled.

How it works

ACOS = ad spend / ad-attributed sales (Amazon Ads definition). TACoS = ad spend / total sales. Organic sales = total sales - ad-attributed sales.

The comparison is arithmetic on your two periods. A falling TACoS is consistent with ads helping organic sales, but it does not prove it: seasonality, price changes, promotions and stock levels also move total sales.

The Amazon Ads ACOS guide defines ACOS as ad spend divided by ad revenue. It does not define TACoS, so on this page TACoS means ad spend divided by total sales (ad-attributed plus organic).

Source (opened 2026-10-18): What is advertising cost of sales (ACOS)? Calculation and tips - Amazon Ads. Everything else is arithmetic on your inputs.

Inputs are user-entered figures. Results are planning estimates, not financial advice or a forecast. This tool is not affiliated with or endorsed by Amazon. Everything runs in your browser. Nothing you type is sent or stored.

FAQ

Which is more important, ACOS or TACoS?

They answer different questions. ACOS tells you whether the ads themselves are efficient. TACoS tells you how heavily the whole business leans on ad spend. Watch both over the same period.

Why did my TACoS fall while ACOS stayed the same?

Total sales grew faster than ad spend. That usually means organic sales rose, though price, seasonality or promotions can also be the cause.

Can TACoS be higher than ACOS?

No. Total sales include ad-attributed sales, so dividing the same spend by a larger number gives a lower or equal percentage.

Does a lower TACoS always mean better?

Not by itself. Cutting ads can lower TACoS and also lower total sales. Compare profit, not only the ratio.