ACoS Calculator
Work out Advertising Cost of Sales from ad spend and ad sales, and see it against your break-even margin.
Your numbers
From the Campaign Manager for the same date range.
Attributed sales for the same campaigns and dates.
Price minus product cost and all Amazon fees, as a share of price. This is your break-even ACoS.
Your result · updates as you type
ACoS
26%
$1,250.00 spent for $4,800.00 in ad sales. Your break-even ACoS is 30%, so these ads make money on the orders they bring in.
- ROAS
- 3.84x
- Break-even ACoS
- 30%
- Profit from ad sales
- $190.00
You have 4% of headroom. You can raise bids on converting keywords until ACoS nears 30%, or keep the gap as profit.
Breakdown
- ACoS = ad spend ÷ ad sales
- $1,250.00 ÷ $4,800.00 = 26%
- ROAS = ad sales ÷ ad spend
- 3.84x
- Gross profit on ad sales (before ad cost)
- $1,440.00
- Minus ad spend
- −$1,250.00
- Profit after ads
- $190.00
ACoS, ROAS and what they mean
Worked example (the calculator's starting values)
- Ad spend
- $1,250.00
- Ad sales
- $4,800.00
- Profit margin before ads
- 30%
ACoS is $1,250 ÷ $4,800 = 26%. ROAS is 3.84x. Since 26% is under the 30% break-even margin, these ads make money: profit from ad sales is $190.00.
At $900 spend and $1,800 in ad sales (the calculator's launch-campaign preset), ACoS is 50%, well above the 30% break-even margin, so those ads lose money on the orders they bring in even though sales look healthy.
Using ACoS to manage campaigns
- Set the break-even margin from your real numbers. Use the break-even ACoS calculator to get it from price, referral fee, FBA fee and product cost, instead of guessing.
- A high ACoS isn't always bad. During a launch, spending above break-even to build reviews and organic rank can be a deliberate trade, as long as you track it and stop once rank improves.
- Pull the numbers from Campaign Manager for the same date range as your sales figures, so ACoS reflects the same period.
What ACoS doesn't show
ACoS looks at ad-attributed sales only, so it says nothing about organic sales your ads may be helping to create. Use the TACoS calculator to see ad spend against total sales, and the ACoS to bid calculator to turn a target ACoS into a maximum cost per click.
Questions people ask
What is a good ACoS on Amazon?
One below your break-even ACoS, which is your profit margin before ad costs. There's no universal target number: a thin-margin product needs a lower ACoS than a high-margin one to stay profitable.
What's the difference between ACoS and ROAS?
ACoS is ad spend divided by ad sales, shown as a percentage. ROAS is ad sales divided by ad spend, shown as a multiple. They measure the same relationship from opposite directions.
How do I lower my ACoS?
Cut bids or pause search terms with clicks and no orders, add negative keywords to stop wasted spend, and improve conversion rate with better images, price and reviews so the same clicks turn into more orders.
Is a high ACoS always a problem?
Not always. Sellers sometimes accept ACoS above break-even during a product launch to win reviews and organic rank, as long as it doesn't continue once the product is established.
Where do I get my ad spend and ad sales figures?
From Campaign Manager in Amazon Ads, for the same campaigns and date range you're checking.
Related tools
Want this builtinto your store?
I'm Emmanuel, a Shopify and WooCommerce developer. If this tool pointed at something you'd rather have fixed for you (a faster store, cleaner product data, a migration, a custom feature), send me a note.
Emmanuel Asika
Shopify & WooCommerce developer, Dublin
I build and fix online stores: new builds, migrations, speed, SEO and the custom bits apps can't do.
Last reviewed 30 September 2026.
Sources: Amazon Ads: What is ACOS? · Amazon: Selling fees (referral fees by category)