Your Amazon PPC ACoS Looks Good – But Is Your Product Actually Profitable?

Is a Low Amazon ACoS Actually Good?

“What's a good ACoS?”

It's one of the most common Amazon PPC questions.

You'll often hear answers like:

20% is good. 30% is acceptable. Anything over 40% is bad.

I don't believe that's a particularly useful way of looking at Amazon PPC.

Because a 20% ACoS could be losing one product money while a 40% ACoS could be commercially acceptable for another.

Context matters.

What Is Amazon ACoS?

Advertising Cost of Sales is:

Ad Spend ÷ Ad Sales × 100

If you spend £200 and generate £1,000 in advertising-attributed sales:

£200 ÷ £1,000 = 20% ACoS

Simple enough.

But this only tells us the relationship between advertising spend and attributed advertising sales.

It doesn't tell us whether the product is actually profitable.

Start With Break-Even ACoS

This is one of the first calculations I want when analysing a product.

Imagine:

Selling price: £30

After product costs, Amazon fees and other variable costs, you're left with:

£9 before advertising

Your pre-advertising margin is therefore approximately:

£9 ÷ £30 = 30%

That gives you an approximate 30% break-even ACoS.

At 30% ACoS, your advertising-attributed sale is roughly breaking even based on those assumptions.

Now compare two products.

Product A may be losing money on its ad-attributed sales, despite the lower ACoS.

Product B, despite the higher ACoS, has potentially more profit left.

That's why asking whether 20% ACoS is “good” without knowing the margin doesn't tell me enough.

But Even Break-Even ACoS Isn't the Whole Story

Amazon PPC doesn't operate in isolation.

Advertising can potentially contribute towards:

• Sales velocity
• Organic ranking
• Keyword visibility
• Reviews over time
• Brand awareness
• Repeat purchases

That's why I also look at TACoS.

Why TACoS Matters

TACoS stands for Total Advertising Cost of Sales.

The calculation is:

Advertising Spend ÷ Total Sales × 100

Imagine:

• Ad spend: £2,000
• Advertising sales: £6,000
• Total Amazon sales: £15,000

ACoS:

£2,000 ÷ £6,000 = 33.3%

TACoS:

£2,000 ÷ £15,000 = 13.3%

Now we have a much more useful picture. We're seeing how much of the product's total revenue is being consumed by advertising.

What I Like to See Over Time

For an established product, one potentially positive pattern is:

Sales increasing + organic sales increasing + TACoS decreasing

That can indicate PPC is contributing towards wider product growth rather than the product becoming increasingly dependent on advertising.

Compare that with:

PPC spend increasing + PPC sales increasing + organic sales flat + TACoS increasing

I'm going to investigate. The advertising may look busy, but are we actually improving the business?

Sometimes a High ACoS Is Deliberate

There are situations where I may accept an ACoS above my normal profitability target. For example:

New Product Launch

I may deliberately invest more aggressively in selected high-value keywords to generate initial sales and establish ranking.

Strategic Keyword Ranking

A keyword may have significant long-term organic value.

New Market Testing

I may accept reduced short-term efficiency while collecting data.

But there's an important difference between deliberately accepting a higher ACoS and having a high ACoS because nobody is controlling the advertising.

One is strategy. The other is waste.

Don't Optimise PPC Until You Damage Sales

I've seen accounts where the solution to high ACoS was effectively:

Reduce every bid.

And yes, ACoS can fall. But so can:

• Impressions
• Clicks
• Orders
• Organic ranking
• Total revenue

You can create a fantastic-looking ACoS by barely advertising. That doesn't necessarily create the best business outcome.

What I Analyse Instead

When I audit PPC for a product, I want to see the relationship between:

• ACoS — advertising efficiency
• TACoS — advertising dependence across total revenue
• ROAS — revenue generated for each £1 of ad spend
• CVR — whether clicks become orders
• CTR — whether shoppers choose the listing
• CPC — what we're paying for traffic
• Margin — whether the economics work
• Organic sales — whether PPC is supporting wider growth
• Total profit — what ultimately matters

No single metric tells the whole story.

Final Thoughts

A low ACoS isn't the objective. Neither is a high ROAS. They're indicators.

The real objective should be to build a profitable, sustainable product.

Before celebrating a 20% ACoS, ask:

• What's my break-even ACoS?
• What's happening to TACoS?
• Are organic sales growing?
• What's happening to total profit?

That's the level at which PPC starts becoming a business strategy rather than simply an advertising dashboard.

Need Help Understanding Your PPC Numbers?

I help Amazon sellers analyse PPC alongside product profitability, total sales and growth.

If you're unsure whether your advertising is genuinely helping your business, Denver James Ltd provides PPC audits, consultancy and coaching for new and established Amazon sellers.