Google AI Max adds budget and ROI A/B testing across Search campaigns

August 21, 2026 · mediapost.com

A demo posted by Google shows an advertiser or agency building an A/B test campaign in ten clicks, using a brand's own parameters and its targets. The demo accompanies an update to AI Max, Google's AI-powered tool for setting up search campaigns: advertisers can now test different budgets and ROI targets across multiple Search campaigns within a single A/B test, rolling out in September. Brandon Ervin, Google's director of product management for Search Ads, wrote in a post on the Google Ads & Commerce blog that the feature will "help you see exactly how scaling up your campaigns impacts your bottom line." Google also added the ability to run A/B tests with brand or location controls enabled, so accounts that rely on those settings can test AI Max without compromising them.

Budget and ROI comparisons across several Search campaigns at once give search teams a faster read on where incremental spend pays back, without building separate manual tests for each campaign. That speed matters because AI Max is set to become the default way to set up search campaigns starting next month, distinct from Performance Max, which spans Search, YouTube, Display, Gmail, Maps and Discover as one cross-channel product. Teams that lean on brand or location controls can confirm AI Max holds those guardrails before rolling it out further.