Amazon's ACOS and TACOS metrics don't translate. Sellers expect 25% ACOS but see 50% 'ACOS' on Google and panic-cut campaigns that are actually profitable.
Example: Cutting 3x ROAS campaigns because '33% ACOS' seems high vs. Amazon's 25%
On Amazon, your product page gets trust from Amazon's brand. On your site, nobody knows you. Cold traffic conversion rates are 3-5x lower than expected.
Example: Expecting 15% conversion rate (Amazon) but getting 3% on Google
Amazon trained customers to expect 1-2 day shipping. Your 5-7 day shipping loses to Amazon on product searches, even when you're advertising.
Example: Customers clicking your ad, seeing 7-day shipping, buying from Amazon instead
Amazon success comes from product optimization. Google success comes from audience targeting. Sellers dump their entire Amazon catalog into Shopping and wonder why nothing converts.
Example: 500 SKU Shopping feed with $3/day per product, none getting enough data
Your Amazon listing has 5,000 reviews. Your website has zero. Social proof that drove Amazon sales doesn't transfer, and new customers don't trust you.
Example: 4.8 stars on Amazon, no reviews on site = 60% lower conversion rate
With a single asset group, Google optimizes for aggregate ROAS by heavily favoring your top 5-10 products. The rest of your catalog gets almost no impressions. Worse, low-margin products drag down profitability while appearing successful in aggregate.
Fix: Segment products by performance tier: Winners (scale), Potentials (test), Underperformers (cut or fix). Create separate asset groups for each.
PMax claims credit for brand searches that would've cost $0.30 through a dedicated brand campaign. Without exclusions, you're paying 3-5x more for customers already looking for you.
Fix: Add brand exclusions to PMax and run a separate Brand Search campaign with exact match keywords.
Missing GTINs, generic titles, no custom labels, and missing sale prices hurt your Shopping ad performance. Amazon-style titles (keyword stuffed)
Fix: DON'T copy Amazon listings directly—rewrite for humans
Your 5x ROAS might look great until you realize 70% of sales are repeat customers who would've bought anyway. You're paying to acquire customers you already have.
Fix: Segment reporting by new vs returning customers. Set up customer match lists and analyze true CAC.
Not all campaign types work for amazon sellers stores. Here's what to skip:
Too many SKUs, not enough data per product
Amazon dominates, you can't compete yet
Need conversion data first
Follow these best practices to maximize your Amazon Sellers Google Ads performance:
Budget: 15-25% • Target ROAS: 5-10x
Budget: 35-45% • Target ROAS: 2-3.5x
Budget: 20-30% • Target ROAS: 2.5-4x
Budget: 10-15% • Target ROAS: 4-8x