Amazon Advertising
By VEONIB Team • Updated July 4, 2026
How to Work Out ACoS on Amazon: The Complete Guide
Quick Answer
ACoS (Advertising Cost of Sale) measures the efficiency of your Amazon PPC campaigns. The formula is simple: divide your total ad spend by the total sales those ads generated, then multiply by 100. An ACoS of 25% means you spend 25 cents in ads for every dollar of sales. Mastering this calculation is the first step to profitable Amazon advertising.
1. The Simple Formula
ACoS stands for Advertising Cost of Sale. It tells you what percentage of your revenue is spent on advertising. The formula is straightforward:
ACoS = (Total Ad Spend ÷ Total Sales) × 100
Where:
- Total Ad Spend = the total amount you paid for all ad clicks in a given period
- Total Sales = the total revenue generated from those ad clicks within the attribution window
The result is a percentage. For example, if you spent $200 on ads and generated $1,000 in sales, your ACoS is ($200 ÷ $1,000) × 100 = 20%.
Think of It This Way
ACoS is like the "cost of ingredients" for the revenue your ads bake. If a bakery spends 20 cents on flour and sugar for every dollar of bread sold, that is a 20% "ingredient cost." The goal is keeping that cost low enough that the remaining profit covers your other expenses and leaves you with a margin.
2. Manual Calculation Walkthrough
Let us walk through a real-world example so you can work out ACoS with confidence.
Step 1: Gather Your Data
Pull your numbers from Amazon Campaign Manager for a specific time period (say, the last 7 days):
- Campaign Total Spend: $450.00
- Total Sales from Ads: $2,250.00
Step 2: Apply the Formula
ACoS = ($450 ÷ $2,250) × 100
ACoS = 0.20 × 100
ACoS = 20%
Step 3: Interpret the Result
A 20% ACoS means for every dollar of ad-attributed sales, you paid 20 cents in advertising. Whether this is good or bad depends on your product's profit margin. If your profit margin is 35%, a 20% ACoS is healthy. If your margin is only 15%, you are losing money on every ad sale.
Step 4: Break Down by Campaign
Now calculate ACoS for individual campaigns. You might find:
| Campaign | Ad Spend | Sales | ACoS |
|---|
| Auto-Target | $180 | $720 | 25% |
| Exact Match | $150 | $1,050 | 14.3% |
| Phrase Match | $120 | $480 | 25% |
This breakdown reveals your Exact Match campaign is most efficient, suggesting those specific keywords are driving highly relevant traffic.
3. Using Amazon's Dashboard
You do not need to calculate ACoS manually every time. Amazon provides ACoS directly in the Campaign Manager dashboard.
- Navigate to Campaign Manager from your Seller Central or Advertising Console.
- View the main table and look for the "ACoS" column. If it is not visible, click the column customization icon to add it.
- Select your date range using the date picker at the top-right. Typical ranges are 7 days, 30 days, or a custom range.
- Click any campaign name to drill into campaign-level ACoS, then further into ad group and keyword-level ACoS.
Amazon also provides Total ACoS, which includes attributed sales from all sources, not just ad clicks. This can be useful for understanding your overall advertising cost impact.
Pro Tip
Download your campaign data as a CSV from Amazon and run the numbers in a spreadsheet. This gives you the flexibility to calculate ACoS by product, by keyword, or by time period that Amazon's default dashboard may not show at a glance. It is especially useful when managing dozens of SKUs.
4. Common Calculation Mistakes
Even experienced sellers make errors when working out ACoS. Here are the most frequent pitfalls:
- Mixing time periods: Comparing ad spend from 30 days with sales from 7 days. Always use identical date ranges for both numbers.
- Including non-ad sales: Using total product sales instead of only ad-attributed sales. This artificially lowers your ACoS and hides inefficiency.
- Ignoring the attribution window: Amazon uses a 7-day click attribution window. A sale on day 8 after a click is not counted. Be aware this can lag your true picture.
- Forgetting returns and refunds: Amazon reports gross sales, not net. If returns are high in your category, your effective ACoS is worse than it appears.
- Looking only at blended ACoS: Averaging all campaigns hides which campaigns are profitable and which are bleeding. Always check ACoS at the campaign and keyword level.
5. Frequently Asked Questions
What is the difference between ACoS and ROAS?
ACoS is your ad spend divided by sales (spend efficiency), while ROAS is sales divided by ad spend (return multiple). An ACoS of 20% equals a ROAS of 5x. ACoS is expressed as a percentage; ROAS as a ratio. Most Amazon sellers use ACoS as their primary metric because it intuitively relates to profit margins.
Is a lower ACoS always better?
Not always. An extremely low ACoS often means you are under-spending and capping your sales volume. During product launches, a higher ACoS (50-100%+) is normal and expected. The optimal ACoS balances profitability with the growth stage of your product. Focus on "profitable ACoS" rather than "low ACoS."
Should I include all sales or only attributed sales?
The standard ACoS formula uses only attributed sales from ad clicks within Amazon's 7-day attribution window. Including total product sales would understate your true ad cost efficiency. Amazon's dashboard shows both "ACoS" (attributed sales only) and "Total ACoS" (including organic halo).
What is a good ACoS for a new product launch?
During launch, ACoS of 50-100% is common as you aggressively bid to win visibility, collect reviews, and build organic ranking. The acceptable launch ACoS depends on your budget and long-term strategy. Most sellers plan to decrease ACoS to 20-30% within 90 days post-launch as organic rankings stabilize.
How often should I calculate ACoS?
Review ACoS at least weekly for active campaigns and daily during launches. Amazon data has a 24-48 hour lag, so account for that. Monthly ACoS trends give the most reliable picture for strategic decisions since daily numbers can fluctuate significantly due to click volume and attribution timing.
Can product videos improve my ACoS?
Yes. Adding a product video to your listing can lift conversion rates by 15-25%. When more clicks convert to sales, your ACoS drops because ad spend stays the same but attributed sales increase. This makes product video one of the most impactful levers for improving ACoS without touching your bidding strategy.