Why your Amazon ACOS is high and what to check

A high advertising cost of sales, or ACOS, means advertising spend takes a large share of the sales attributed to those ads. Before lowering every bid, check whether the problem comes from expensive clicks, weak conversion or a target that does not fit the product's margin. Amazon defines ACOS as ad spend divided by ad-attributed sales, expressed as a percentage.¹

Calculate what the product can afford

Suppose an order produces $40 in net sales. Product cost, marketplace fees, fulfilment and an allowance for expected returns total $28. That leaves $12 before advertising and fixed overhead. In this simplified example, spending $12 to acquire the order uses the entire contribution. The corresponding ACOS is 30%. Spending $8 leaves $4 before fixed overhead, giving an ACOS of 20%.

These are illustrative figures, not a recommended target. Use your actual costs, treat taxes consistently and account for discounts and refunds. Repeat the calculation by product; an account average can hide products that lose money.

Separate targeting from conversion

Export campaign and search-term data for a consistent period, allowing for the applicable reporting delay and attribution window. Review the actual shopper searches and product placements that spent money. Group them into relevant buyers, unclear intent and obvious mismatches. Negative targeting can help exclude unsuitable searches or products, but its scope depends on the campaign and targeting type.²

Then inspect the detail page. Is the advertised variation available? Does the main image communicate the product? Can a buyer understand size, compatibility and quantity? Is the delivered price competitive for the value offered? A bid change cannot repair inaccurate product information.

Make one decision at a time

Build a short change log with the target, spend, attributed sales, reason for action and review date. Reduce exposure to confirmed mismatches. Give relevant but inconclusive targets a defined test budget based on what the business can afford to learn. Avoid a universal rule that every target must be paused after the same number of clicks.

For example, two targets could each spend $30 without a sale. One may be irrelevant to the product; the other may have too little evidence for a high-priced item. The same spend does not justify the same decision. Set limits deliberately and avoid extending a test indefinitely because you hope it will recover.

Check the business result

Compare ACOS with total sales, contribution and inventory availability. TACOS is ad spend divided by total sales for the chosen scope and period. It provides another view of advertising dependence, but it does not prove that ads caused organic sales. Keep the currency and revenue definitions consistent.

Amazon's Sponsored Products guidance links advertising preparation with product-page readiness.³ Review the offer before increasing spend, and judge changes over enough comparable data to avoid reacting to normal daily variation.

Need a structured review? Explore Ecomtik's Amazon PPC management. If shoppers already click but do not buy, continue with the conversion checklist.

Footnotes

1. Amazon. Amazon Ads guide to ACOS ↩

2. Amazon. Amazon Sponsored Products targeting guide ↩

3. Amazon. Amazon review of Sponsored Products best practices ↩