Amazon TACOS Calculator

Behind the number

Total advertising cost of sale is ad spend divided by total sales, organic and paid together: TACOS = spend ÷ total sales × 100.

Where ACOS asks how efficiently the ads converted, TACOS asks what share of the whole business the advertising consumes. They can move in opposite directions, and when they do the difference is informative.

It is the closest thing Amazon sellers have to a marketing-efficiency ratio for the account.

A real example

$1,200 of ad spend, $6,000 of attributed sales and $18,000 of total sales. ACOS is 20% and TACOS is 6.7%.

Two thirds of revenue is organic, so the advertising is supporting a listing that largely sells itself. That is a healthy position.

Now the same $1,200 producing $6,000 attributed out of $7,000 total. ACOS is still 20% and TACOS is 17.1%, almost everything is paid, and the listing has no organic strength.

Identical ACOS, completely different businesses. The first survives an advertising pause; the second stops.

The usual mistakes

TACOS falls both when organic sales grow and when advertising is cut, and those are opposite situations. Reading a falling TACOS as success without checking whether total sales are rising is a common error.

It is also a lagging measure during a launch, when advertising is deliberately heavy and organic rank has not yet built. A high TACOS in the first two months is expected rather than a problem.

Using the result

Track TACOS alongside total sales rather than alone. Falling TACOS with rising sales is organic growth; falling TACOS with flat sales is retreat.

Then set a target trajectory rather than a number. A launch might run at 25% TACOS falling to 8% over six months, and the shape of that curve is the thing to manage.

What the trajectory tells you about a product

A product whose TACOS falls steadily as sales grow has found genuine organic demand: the advertising bought rank, the rank is holding, and each additional sale costs less to acquire than the last.

A product whose TACOS stays flat while sales grow is buying every increment. It can still be profitable, but it has no compounding and no defensibility, because a competitor with deeper pockets can outbid it at any point.

A product whose TACOS rises is losing ground, either competition has intensified or the listing has stopped converting. That pattern is worth investigating immediately, because it usually precedes a decline in rank that is much harder to reverse than to prevent.

One practical note on measurement: TACOS is only meaningful over a period long enough to smooth promotional spikes and stockouts, so a weekly figure is noise. Monthly is the shortest useful interval, and a three-month rolling view is what makes the trajectory visible.

It is worth calculating at brand level as well as product level. A hero product carrying advertising that drives traffic across a range will show a worse TACOS than it deserves, while the products benefiting from that traffic show a flattering one.