CSS and Performance Max: where the discount applies and where it does not

The CSS saving applies to the Shopping component of Performance Max, to standard Shopping campaigns and to Demand Gen with a product feed. It does not apply to Search, Display, YouTube or free listings. Each case explained, and how to measure the effect properly.

By Updated: 5 min read

The most common question after "how much do I save?" is "does it work with Performance Max?". Short answer: yes, for the Shopping part, which for most stores is also the biggest part of the spend. The full answer, by campaign type, below.

In short: where it applies

Campaign type or placementCSS saving applies?Why
Standard ShoppingYesEvery Shopping ad in Europe is placed through a CSS
Performance Max, Shopping component (product ads from the feed)YesThe same Shopping ads, placed through the same CSS
Performance Max: Search, Display, YouTube, Discover, Gmail componentsNoThey do not go through a CSS
Demand Gen with a product feedPartlyOnly placements that show feed products through the Shopping carousel
Free listings in the Shopping tabNot applicableNo auction, so no cost to reduce; they stay active
Search (text), Display, YouTubeNoNothing to do with the CSS

How it works with Performance Max

Performance Max is an umbrella campaign: from one budget, Google places ads on Search, Display, YouTube, Discover, Gmail, Maps and Shopping. The Shopping component (ads with image, price and store) is placed through the CSS linked to your Merchant Center account, exactly like a standard Shopping campaign. So after moving to a partner CSS, 100% of your bid enters the Shopping auctions instead of ~80%.

What you do not see in Google Ads: Performance Max does not show a separate "Shopping CPC". The effect shows up in aggregate: for the same budget, more Shopping impressions and clicks, a lower cost per conversion or a better ROAS. That is why with Performance Max you should compare cost per conversion and conversion value over 30 days before and after, not CPC.

A useful detail: in the Insights report or the listing-group segmentation you can see how much of the Performance Max spend goes to products. In typical stores it is between 60% and 90%, so the CSS saving reaches most of the budget.

Save up to 20% on every Google Shopping click

Bigconvert CSS: €18.99 per month per store, no commission, cancel anytime. Activation takes 5 minutes.

Activate Bigconvert CSS

How to measure the effect properly

  1. Before the switch, note the last 30 days: cost, clicks, average CPC (standard Shopping), conversions, cost per conversion, impression share.
  2. Do not change budgets, bidding strategies or campaign structure in the first 2–4 weeks after the switch; otherwise you cannot tell what caused what.
  3. Compare the 30 days after with the 30 before. Mind the season: a switch on 1 November will be "helped" by Black Friday.
  4. With manual (CPC) bidding you see the lower CPC or more clicks at the same CPC directly. With automated bidding you see more conversions or a lower cost per conversion.

Free listings and the Shopping tab

Your feed products also appear for free in the Shopping tab (free listings). These are not bid on and not paid for, so there is no cost to reduce. They stay active whatever CSS you use, because they are tied to the Merchant Center account, not to the CSS. The "By [CSS]" label does not appear on free listings.

Frequently asked questions

Do I need to change anything in my Performance Max campaign after switching to a CSS?expand_more

No. The campaign runs unchanged; the Shopping component automatically goes through the new CSS.

Why do I not see a lower CPC in Performance Max?expand_more

Because Performance Max optimises automatically towards conversions and does not report the Shopping CPC separately. The effect shows as more conversions or a lower cost per conversion at the same budget.

Does it apply to Demand Gen too?expand_more

Only to placements with feed products shown in the Shopping carousel. Video or image ads in Demand Gen do not go through a CSS.

Save up to 20% on every Google Shopping click

Bigconvert CSS: €18.99 per month per store, no commission, cancel anytime. Activation takes 5 minutes.

Activate Bigconvert CSS

Read next

What is Google CSS and how does it lower your Google Shopping cost per click
A CSS (Comparison Shopping Service) is a price comparison service through which stores place their Google Shopping ads. Through a partner CSS, your whole bid enters the auction instead of about 80% of it. Here is where the difference comes from, what changes in your account and what it costs.
How to switch to a partner CSS in Google Merchant Center, step by step
Switching to a CSS takes a few minutes and is done through an approval in Merchant Center. The exact steps, what you see in your account, how to check which CSS you use now, what to do with Google Shopping afterwards and how to go back if you want.
How much does a Google CSS cost: pricing models, public prices and when it pays off
A partner CSS costs between nothing and a few hundred euros a month depending on the model: flat fee, percentage of ad spend or bundled in an agency fee. Public prices of the main CSSs in Europe (October 2026) and a simple calculation to see from which budget it is worth it.