ACoS is the number every Amazon advertiser stares at, but “is mine good?” is harder to answer than it looks. A good ACoS for one product is a disaster for another, because it depends entirely on your profit margins. This guide explains what ACoS is, how to calculate it, and how to work out the right target for your specific products rather than chasing a generic benchmark.
Quick Answer
A good ACoS on Amazon is one that leaves you profitable, which depends on your margins, not a fixed number. Many sellers aim for 15 to 30%, but the real target is your break-even ACoS, the point where ad cost equals profit margin. Anything below break-even is profitable; the right goal sits comfortably under it.
Key Takeaways
- ACoS is ad spend divided by ad sales, as a percentage.
- A “good” ACoS depends on your profit margin, not a benchmark.
- Break-even ACoS equals your profit margin before ad cost.
- Below break-even is profitable; above it loses money.
- Launch and defense campaigns can justify a higher ACoS.
Table of Contents
- What ACoS Means
- How to Calculate It
- Your Break-Even ACoS
- So What Is a Good ACoS?
- When a High ACoS Is Fine
- FAQs
What ACoS Actually Means
ACoS stands for Advertising Cost of Sales. It is the percentage of your ad-generated revenue that you spent on the ads themselves. A 25% ACoS means you spent 25 cents in advertising for every dollar of sales those ads produced. Lower generally means more efficient, but as you will see, lower is not always the goal. If you are new to all this, start with our guide on what Amazon PPC is.
How to Calculate ACoS
The formula is simple:
| Formula | Example |
|---|---|
| ACoS = (Ad Spend / Ad Sales) x 100 | $250 spend / $1,000 sales = 25% |
So if you spent $250 on ads and those ads produced $1,000 in sales, your ACoS is 25%. That is all there is to the math. The harder question is whether 25% is good for your product.
Your Break-Even ACoS Is the Key Number
This is what most ACoS advice skips. Your break-even ACoS is the point where your ad cost exactly equals your profit margin, meaning you make no profit and no loss on that sale. It equals your profit margin before advertising.
Example: a product sells for $30. After Amazon fees, product cost, and shipping, your profit is $12, a 40% margin. Your break-even ACoS is 40%. At 40% ACoS you break even on ad sales. Below 40%, every ad sale is profitable. Above 40%, you lose money on ad sales. Suddenly “is 25% good?” has a clear answer: yes, because it is well below your 40% break-even.
So What Is a Good ACoS?
A good ACoS is one comfortably below your break-even, leaving healthy profit. For a typical product with a 35 to 45% margin, many sellers target a 15 to 30% ACoS on established, profitable campaigns. But treat those numbers as a starting reference, not a rule. A high-margin product can profit at a 40% ACoS; a thin-margin product might need to stay under 15%. Your margin sets your target.
When a High ACoS Is Actually Fine
Sometimes a high or even above-break-even ACoS is the right call:
- Product launches, where you spend aggressively to build ranking and velocity, accepting short-term losses for long-term position.
- Defending brand terms, where keeping competitors off your branded searches is worth the spend.
- Clearing inventory before long-term storage fees hit.
The point is that ACoS is a tool, not a scorecard. The right number depends on your margin and your goal for that campaign. For the bigger picture, see whether Amazon PPC is worth it and how to lower your ACoS once you know your target.
If you want your campaigns managed to the right ACoS target for each product, that is what we do. Our Amazon PPC management service is built around profitability, and you can see the results on our client results page.
Frequently Asked Questions
What is a good ACoS on Amazon?
One that leaves you profitable, which depends on your margin rather than a fixed number. Many sellers aim for 15 to 30% on established campaigns, but the real target is comfortably below your break-even ACoS, which equals your profit margin.
How do I calculate ACoS?
Divide your ad spend by your ad sales and multiply by 100. For example, $250 of spend producing $1,000 in sales gives a 25% ACoS. The math is simple; judging whether the number is good requires knowing your margin.
What is break-even ACoS?
It is the ACoS at which your ad cost equals your profit margin, so you make no profit and no loss on that ad sale. It equals your profit margin before advertising. Below it you profit; above it you lose money.
Is a lower ACoS always better?
Not always. A very low ACoS can mean you are underspending and missing profitable sales, especially on high-margin products. The goal is the most profit, which sometimes means spending more at a higher but still-profitable ACoS.
Why is my ACoS high?
Common causes include bidding too high, targeting irrelevant keywords, a weak listing that does not convert clicks, or strong competition. A high ACoS during a launch can be intentional, but otherwise it usually signals something to fix.
Written by the AMZ Scaler Team
Amazon advertising and listing specialists with 5+ years managing PPC and listing optimization for brands across the US, UK, and Canada. We publish what we apply in real seller accounts every day.
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