Why TACOS matters more than ACOS

A good ACOS can make an Amazon account look healthier than it actually is.

ACOS is probably one of the first numbers most people look at when reviewing Amazon advertising. And understandably so. If you're spending £1,000 on ads and generating £10,000 in attributed sales, you've got a 10% ACOS.

On the face of it, that's excellent.

But there is a problem.

It tells me how the advertising is performing. It doesn't tell me how the Amazon account is performing.

That's why, when I'm looking at an established account, I normally want TACOS sitting alongside it.

ACOS only tells part of the story

The calculation for ACOS is straightforward:

Ad spend ÷ attributed ad sales × 100

Spend £1,500 and generate £10,000 of attributed sales and your ACOS is 15%.

Useful information.

Now let's say the account generated £12,000 in total sales during the same period.

That means £10,000 of the £12,000 came through advertising.

That's a very different situation from an account spending the same £1,500, generating the same £10,000 of attributed ad sales, but doing £30,000 in total sales.

Both accounts have a 15% ACOS.

I wouldn't look at those two accounts in remotely the same way.

The second account has significantly more sales happening outside of directly attributed advertising. That could be coming through organic rankings, repeat purchases, brand searches or other traffic.

The first account is much more dependent on paid traffic.

ACOS doesn't show you that difference.

TACOS does.

What is TACOS?

TACOS stands for Total Advertising Cost of Sales.

Instead of comparing advertising spend against advertising sales, you're comparing it against total Amazon sales.

The calculation is:

Ad spend ÷ total sales × 100

Take the first example.

£1,500 advertising spend.

£12,000 total sales.

That's a 12.5% TACOS.

Now take the second account.

Same £1,500 advertising spend.

£30,000 total sales.

That's a 5% TACOS.

Same advertising spend.

Same attributed advertising revenue.

Same ACOS.

Completely different commercial picture.

That's why I don't like looking at ACOS in isolation.

What I actually want advertising to do

Advertising shouldn't exist in its own little world.

Yes, I want campaigns to generate sales efficiently. But ultimately I want advertising activity to contribute towards making the wider Amazon account stronger.

That might mean getting a new product moving.

It might mean improving sales velocity on an existing product.

It might mean defending an important search term.

It might mean pushing a product further up the organic results for commercially valuable keywords.

And sometimes it simply means profitably putting more products in front of customers.

The important part is understanding why you're spending the money.

If sales are increasing while TACOS gradually comes down, that's usually an interesting sign.

You're spending money on advertising, but advertising is accounting for a smaller percentage of the total revenue being generated.

That's often exactly what I want to see.

A low ACOS isn't always the goal

This is where Amazon PPC can get unnecessarily obsessed with one number.

Imagine a campaign running at 8% ACOS.

Looks brilliant.

So you protect it.

Budgets stay conservative. Bids stay low. Nobody wants to upset the lovely ACOS number sitting in the report.

But perhaps that product has a healthy margin, converts extremely well and has room to take significantly more market share.

Would I accept a 12% or 15% ACOS if it meant considerably more revenue and helped grow the wider product?

Potentially, absolutely.

The objective isn't to win an award for having the lowest ACOS.

It's to build a commercially healthy Amazon channel.

There are also situations where I'd deliberately tolerate a much higher ACOS.

A product launch is the obvious example.

If a new ASIN has no sales history, no reviews and weak organic positioning, expecting advertising to immediately behave like an established bestseller isn't realistic.

The advertising has a job to do.

That doesn't mean throwing money at it indefinitely. It means understanding what stage the product is at and judging the numbers in context.

TACOS can expose advertising dependency

This is probably where I find TACOS most useful.

If an account is doing strong revenue, I want to understand how much of that revenue is being propped up by advertising.

If total sales increase but TACOS keeps climbing with them, I'd start asking questions.

Are we genuinely growing?

Or are we simply buying more revenue?

Are organic positions improving?

Are we spending heavily on branded searches that customers may have found us through anyway?

Are certain products unable to generate meaningful organic sales?

What happens if we reduce advertising spend?

Those questions matter because an Amazon account can look fantastic at the top line while becoming increasingly expensive underneath.

Revenue alone doesn't tell you that.

Neither does ACOS.

But falling TACOS isn't automatically good either

This is where metrics need some common sense applied to them.

You could cut advertising spend dramatically tomorrow and your TACOS might fall.

That doesn't mean you've made a brilliant commercial decision.

If total revenue subsequently falls, organic positions deteriorate and competitors start taking visibility, you've simply made the percentage look nicer.

The same applies to ACOS.

Metrics need context.

I generally want to look at the relationship between:

Total revenue
Advertising revenue
Advertising spend
ACOS
TACOS
Conversion rate
Traffic
Organic positioning
Margin

Then I want to understand what's actually causing the movement.

One number rarely gives you the answer.

Where ACOS is still extremely useful

None of this means ACOS isn't important.

It absolutely is.

At campaign, ad group, keyword and product level, ACOS is incredibly useful for understanding where advertising money is working and where it isn't.

If one search term is spending heavily without converting, I want to know.

If one product is running at 40% ACOS while another comparable product is running at 12%, I want to investigate why.

If branded traffic is masking terrible generic keyword performance, I want to separate it.

ACOS is a very useful advertising metric.

I just don't think it should automatically be treated as the main measure of whether an Amazon account is healthy.

That's a different question.

The number I care about depends on what I'm trying to achieve

When I look at Amazon advertising, I'm not really looking for a universally "good" ACOS or TACOS.

I'm looking for context.

What margin does the product have?

Is it established or launching?

What's happening to organic sales?

What keywords are we trying to gain visibility for?

Are sales increasing?

Are we profitable?

How reliant is the account on advertising?

And, most importantly:

Is the money we're spending helping build a stronger Amazon business?

That's the conversation TACOS forces you to have.

ACOS tells you how efficiently your advertising generated attributed revenue.

TACOS starts telling you how advertising fits into the performance of the account as a whole.

You need both.

But if I'm trying to understand the health and direction of an established Amazon account, I'm looking beyond ACOS very quickly.

What I'd look at in your Amazon account

If an account is spending consistently on Amazon Ads, I wouldn't start by simply asking whether the ACOS is good or bad.

I'd look at where the spend is going, which products and search terms are actually driving growth, how much revenue is coming through paid versus organic activity, what the margins can support, and whether TACOS is moving in the right direction as the account grows.

Because the objective isn't just better advertising.

It's a better Amazon business.

Northline Commerce audits Amazon accounts across advertising, catalogue, SEO, account health and commercial performance.

If the numbers look good but you're not entirely sure what's driving them, a marketplace audit is a sensible place to start.