The main difference is that AI Max is a set of AI features you enable within a Search campaign, whereas Performance Max (PMax) is a separate campaign type that advertises across Google's different channels. [1][2]
Both use Google's AI to identify advertising opportunities, but they differ in where adverts appear and how much control you retain.
AI Max vs Performance Max
| Feature | AI Max | Performance Max |
|---|---|---|
| Campaign type | An optional feature within Search campaigns | A separate campaign type |
| Where adverts appear | Google Search, including eligible AI Mode placements | Search, Shopping, YouTube, Display, Discover, Gmail and Maps, plus eligible AI Mode placements |
| Keywords | Uses existing keywords and can expand beyond them | Uses search themes and other signals rather than traditional keyword targeting |
| Ad creation | Uses existing Search ads and can generate additional text | Combines assets such as headlines, descriptions, images and videos |
| Landing pages | Can select relevant pages when Final URL expansion is enabled | Can also select relevant pages when Final URL expansion is enabled |
| Control | Generally more control over keywords and Search campaign structure | More automated across channels |
| Reporting | Search-focused reporting, including AI Max-specific search term information | Campaign and channel-level reporting, with different levels of detail |
How AI Max Works in Practice
Imagine you're running a Search campaign for business car leasing.
You have keywords such as:
- Business car leasing
- Company car lease deals
- Business electric car leasing
Without AI Max, Google matches your adverts to searches according to your keyword match types and other campaign settings.
With AI Max enabled, Google can go beyond your existing keywords by considering their meaning, your adverts and your landing-page content. [1]
For example, it might identify a relevant opportunity for a search such as:
"What's the most cost-effective way to get electric company cars for my employees?"
Even though you haven't specifically added that phrase as a keyword.
AI Max also offers two other features:
Text customisation: Google can generate or adapt advert text to make it more relevant to the search.
Final URL expansion: Google can select a different relevant landing page from your website rather than always using the URL specified in your advert. [3]
Both can be switched off independently, although Final URL expansion requires text customisation. [3]
How Performance Max Differs
Performance Max goes further.
Rather than concentrating on Search, it uses Google's advertising inventory across multiple channels. [2]
For example, someone might initially see your advert on YouTube, later encounter a Display advert and eventually click a Search advert.
PMax uses conversion goals, audience signals, search themes and other information to decide where and when to advertise. [2]
However, you have less direct control over how the campaign distributes its budget across Google's advertising channels.
Which Would I Recommend?
For a business that already relies on Search advertising and wants to test broader search matching while retaining its existing campaign structure, AI Max may be a more manageable starting point.
For a business that wants to reach customers across Google's advertising channels, Performance Max may be appropriate, provided there is sufficient conversion data and a clear commercial objective.
Neither is automatically better. The choice depends on the campaign's purpose, available budget, conversion data and the amount of control you need.
References
[1] Google Ads Help – How AI Max for Search campaigns works.
Explains AI Max's search term matching, keyword expansion, targeting controls and reporting features.
https://support.google.com/google-ads/answer/15910187
[2] Google Ads Help – About Performance Max campaigns.
Explains Performance Max campaign types, advertising channels, audience signals, search themes and campaign controls.
https://support.google.com/google-ads/answer/10724817?hl=en-GB
[3] Google Ads Help – About Final URL expansion in Search.
Explains how Final URL expansion works with AI Max and its dependency on text customisation.
https://support.google.com/google-ads/answer/16230205
[4] Google Ads Help – About ads in AI-powered experiences in Google Search.
Explains how AI Max and Performance Max adverts can appear in AI Mode and how contextual matching differs from direct query matching.
https://support.google.com/google-ads/answer/18826097
