Google Ads

Google Ads AI Max: What It Actually Does, and What to Check Before It Changes Your Campaigns

6 min read

9/4/26, 9:46 AM

There is a small game a lot of paid search managers have been playing this year. You turn off the "Optimize your campaign with AI Max" toggle. You click through the flow. Somewhere between the ad group and the review screen, it is on again. You turn it off. Repeat until one of you gives up.

The joke lands because the underlying shift is real. "Opt in" used to describe a decision you made. In Google Ads in 2026, it increasingly describes a default you did not turn off in time, and as of September 1, a default that Google is applying to existing campaigns on your behalf.

This is a working guide to Google Ads AI Max: what sits inside the toggle, what Google is migrating this month, what the independent performance data actually shows, and how to keep the parts you want without inheriting the parts you don't.

What AI Max actually is

AI Max is not a new campaign type. Google describes it as a suite of targeting and creative features that layers onto your existing Search campaigns and optimizes them in real time. That distinction matters more than it sounds. Performance Max asked you to build something new and accept a black box. AI Max takes the campaign you already built, keeps its history and structure, and changes how it matches queries and what copy it serves.

So the question is not "should I run AI Max instead of Search?" It's "which of these five behaviors do I want operating inside a campaign I already trust?"

The five features inside one toggle

Search term matching. Expands reach beyond your keywords using broad match plus keywordless technology, learning from your current keywords, creatives and URLs to find relevant queries. This is the feature doing most of the heavy lifting and most of the damage when it goes wrong.

Text customization. Generates ad copy from your existing ads, landing page content, assets and domain. It is enabled by default when you switch AI Max on manually.

Final URL expansion. Sends traffic to whichever URL on your domain Google judges most relevant to the query. It depends on text customization: disable text customization and final URL expansion switches off with it.

Brand controls. Brand inclusions and exclusions, set at campaign level, and inclusions can also be set per ad group where they override the campaign setting. If you run in a category with aggressive competitor bidding, this is not optional.

Locations of interest. Ad-group-level targeting based on the geographic intent inside a query, including on keywordless matches.

Two supporting controls are worth knowing: URL exclusions (campaign level, keeps traffic off specific pages) and URL inclusions (ad group level, points expansion at pages you choose). Both require text customization and final URL expansion to be active and both are ignored entirely if you later switch AI Max off, which is a quiet trap if you turn it off and on again.

What Google migrated in September 2026

Google set a migration timeline this summer, and the first window is open right now.

Date	What happens
Aug 3, 2026	You can no longer create new campaign-level broad match settings or legacy automatically created assets (ACA)
Sept 1–30, 2026	Existing broad match and ACA campaigns are automatically converted to AI Max, in place
Sept 2026	In-account notices begin encouraging voluntary Dynamic Search Ads upgrades
Jan 15, 2027	Reminder notifications about legacy DSAs
Feb 1–28, 2027	Automatic DSA migration
Sept 2027	Older API versions supporting legacy features sunset

The settings you inherit depend on which cohort your campaign fell into. Campaigns using campaign-level broad match get AI Max enabled with search term matching on, text customization off and final URL expansion off. Campaigns using standalone ACA get AI Max enabled with search term matching on, text customization on and final URL expansion off.

Google's framing is that this preserves existing behavior. Broadly it does, a broad match campaign was already matching loosely. But "preserved behavior" and "the same settings you would have chosen" are not the same thing, and the campaign now sits under a toggle whose defaults can change again.

The pre-emptive opt-out, turning campaign-level broad match to "Off: use keyword match types," or ACA to "Off: use only assets I provide" — had to happen before September 1. If you missed it, you are now managing the conversion after the fact rather than preventing it. That is a settings audit, not a crisis, but it does need to happen deliberately.

What the performance data actually shows

Google's own figure is that advertisers typically see 14% more conversions or conversion value at a similar CPA or ROAS, rising to 27% for campaigns using exact and phrase match keywords. Read the footnote: that number excludes retail.

The most useful independent counterweight comes from Mike Ryan at Smarter Ecommerce, who analyzed 250+ retail campaigns. The median campaign saw a 13% increase in conversion value, and a 16% increase in CPA, with ROAS outcomes ranging from +42% to −35%. His summary is worth quoting: turning on AI Max is "essentially a coin toss: you may see a lift, but efficiency likely won't follow."

Other findings worth weighing before you commit budget:

Cannibalization. In some accounts, up to 63% of AI Max's expanded coverage was recycling queries the account already reached. Incremental volume and reported volume are not the same thing.
Competitor brand hijacking. One account saw 69% of impressions consumed by competitor brand terms, which is what brand exclusions exist to prevent.
Traffic quality. Lunio analyzed 414 million retail ad clicks across 88 accounts from Q4 2025 to Q2 2026. By Q2 2026, AI Max campaigns carried an invalid traffic rate of 5.28% against 3.08% for standard Search in the same accounts, 72% higher. AI Max's rate more than doubled over the period while standard Search stayed broadly flat.
Search Partner Network. A 0.07% conversion rate versus 3.04% on Google Search in Smarter Ecommerce's analysis.

And the other side of the ledger: Location3 ran a two-month controlled test across five home services franchise locations (December 2025 – January 2026) and saw conversion lifts of 97%, 318%, 350%, 410% and 720%. CPA improved at three of the five locations, held flat at one and rose slightly at one. Accounts with thin keyword coverage and genuine long-tail demand tend to gain. Mature, well-structured accounts and B2B advertisers more often see audience misqualification and creative drift.

When AI Max is worth turning on

The pattern in the data is consistent enough to act on.

Turn it on, carefully, when: your account has long-tail demand you have never captured, your landing page inventory is deep and genuinely relevant, your conversion tracking is clean enough to detect a CPA change inside four weeks, and you sell something with a wide range of ways to ask for it.

Leave it off, or run search term matching only, when: your ICP is narrow and the wrong lead costs you sales time, your brand competes in a category where competitors bid on your terms, your landing pages are few and specific, or your account is already mature and tightly matched in which case expansion is more likely to recycle coverage than add it.

The middle path is underrated: enable AI Max with search term matching only, leave text customization and final URL expansion off, and add brand exclusions on day one. You get the query expansion without handing over your ad copy or your landing page routing. If search term matching earns its place over 4–6 weeks, layer text customization on next one variable at a time.

How to check and control your settings

Find the toggle. Campaigns → Settings → select the Search campaign → AI Max in the section menu. Ad-group-level controls for search term matching, URL inclusions and brand inclusions live under Ad groups.
Audit every migrated campaign individually. Cohort defaults differ, and the setup flow's defaults differ from the migration defaults. Do not assume.
Set brand exclusions before you spend. Campaign level. This is the single highest-value control in the set.
Add URL exclusions for pages that should never receive paid traffic, careers, support docs, legal, out-of-stock categories.
Read the search terms report weekly. Expanded queries carry an "AI Max" match type value, and a Source column shows what drove the match. Negative keywords still work; use them.
Watch the copy. Text customization generates headlines from your site. Review what is actually serving, and use text guidelines to constrain it.
Benchmark against a clean baseline. Compare a 4-week pre-migration window against post, on CPA and lead quality, not click volume.

None of these controls is promised to exist forever. Google's documentation does not commit to keeping them available indefinitely, which is the strongest argument for building your measurement now, while you can still isolate what changed.

Running Search campaigns that were migrated this month? A structured settings and performance review will tell you what changed and what it cost. → Google Ads audit

Sources

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