Google doubles search themes limit for performance max campaigns

Google's recent update to Performance Max campaigns expands the maximum number of search themes from 25 to 50 per asset group. This change, quietly rolled out yesterday, represents another step in Google's effort to balance automation with advertiser control in its advertising platform.

Google has doubled the maximum number of search themes that advertisers can add to Performance Max (PMax) campaigns, increasing the limit from 25 to 50 per asset group. This update allows marketers to provide more explicit guidance to Google's algorithms about which search queries their campaigns should target.

The expanded limit was first discovered by Google Ads specialist Pronay Roy, who shared the finding with Thomas Eccel. Eccel subsequently posted about the update on LinkedIn on May 2, 2025, noting that the feature is "already live in many accounts" though not yet universally available. Some advertisers in Germany reported still being limited to 25 themes, suggesting a phased rollout approach.

According to Search Engine Land, the rollout appears to be happening in stages, with some accounts already having access to the expanded limit while others still operate under the previous 25-theme cap. The publication confirmed the update on May 2, 2025, just one day ago.

Search themes function as signals to Google's artificial intelligence systems that power Performance Max campaigns. Unlike traditional keywords that directly trigger ad placements, search themes serve as directional guidance for the automated systems.

These optional prompts tell Google's algorithms which search queries the advertiser's target audience is actually using. As Eccel explained in his LinkedIn post, search themes "don't restrict your reach. They add to what Google would already target."

Search themes are prioritized similar to phrase or broad match keywords in standard Search campaigns. The system treats them as signals rather than strict targeting parameters, maintaining the flexibility of Google's automated targeting while giving advertisers more influence over ad delivery.

Technically, the themes work alongside other signals including:

• Assets provided in the campaign
• Landing page content
• Audience signals
• Other targeting parameters

The implementation history shows a gradual expansion of control: the feature initially launched with a limit of 10 themes, was increased to 25 in late 2023, and now sits at 50 themes per asset group.

This update comes at a significant moment in Google's advertising ecosystem development. Performance Max campaigns, which automatically place ads across Google's properties including Search, Display, YouTube, Gmail, and Maps, have become increasingly central to Google's advertising strategy.

The search themes functionality was originally introduced to address advertiser concerns about lack of control in these highly automated campaigns. By allowing more search themes, Google is responding to feedback from marketers who wanted additional influence over automated targeting decisions while still leveraging Google's machine learning capabilities.

Some advertisers had complained that the previous 25-theme limit was too restrictive, especially for accounts with broad product lines or diverse customer segments. This was particularly problematic for large retailers and businesses operating across multiple verticals or with extensive product catalogs.

The significance for the marketing community extends beyond the simple number increase. This update represents part of Google's broader strategy to maintain its automation-first approach while making incremental concessions to advertisers who desire more control. For professionals managing complex accounts, the additional capacity to provide intent signals offers meaningful improvements in campaign targeting precision.

The expanded limit enables several strategic applications for digital marketers:

First, advertisers can now add their best-performing search terms from traditional campaigns, creating more alignment between automated and manually managed campaigns. This bridges the gap between conventional search marketing approaches and Google's newer AI-driven platforms.

Second, marketers can more closely align creative assets with specific user intents. By grouping related themes and matching them with appropriate creative elements, advertisers can create more cohesive user experiences across the purchase journey.

Third, the increased limit allows for more granular segmentation of themes by product category, customer segment, or buyer journey stage. This can lead to more precise audience targeting without sacrificing the reach benefits of automated campaigns.

For agencies and in-house teams managing large accounts, the change provides more opportunities to apply strategic thinking within Google's increasingly automated framework. While the fundamental automation-first approach remains unchanged, the expanded controls allow more human expertise to guide machine learning systems.

Importantly, negative keywords still apply to Performance Max campaigns, giving advertisers another layer of control over ad delivery. This means marketers can exclude irrelevant searches while using the expanded search themes to guide targeting toward desired queries.

The update enables several optimization opportunities:

• Adding high-performing historical search terms to guide automation
• Creating more thematically focused asset groups
• Developing more precise targeting strategies without limiting automation's reach
• Testing different theme groupings to identify optimal performance patterns

While the limit increase offers more flexibility, it also introduces complexity. Marketers will need to develop testing strategies to determine whether using more themes actually improves campaign performance or whether more focused groupings remain optimal.

The response from the industry has been cautiously positive. Digital marketing specialists noted that this represents a meaningful increase in advertiser control while maintaining Google's automation-first strategy.

Some specialists have interpreted this update as an indication that Google is gradually responding to advertiser feedback about control limitations in Performance Max campaigns. Others see it as part of a natural evolution toward finding the right balance between automation and human guidance in digital advertising.

The response from professionals in the comment threads of Eccel's LinkedIn post reflected practical interest, with several asking about availability in their markets and accounts. The fact that the feature appears to be rolling out gradually rather than simultaneously across all accounts has created some confusion about availability.

This update signals potential future developments in Google's approach to balancing automation with advertiser control. As machine learning systems continue to evolve, Google appears to be finding ways to incorporate human guidance without compromising the core benefits of automation.

The incremental increase in search themes limits (from 10 to 25 to 50) suggests Google is taking a measured approach to expanding advertiser control, testing impacts at each stage before proceeding further.

For marketing professionals, this update reinforces the importance of understanding both the technical implementation of Google's systems and the strategic opportunities they present. Those who can effectively balance technical knowledge with strategic thinking will be best positioned to leverage these expanded controls.

Timeline

• Late 2021: Performance Max campaigns launch without search themes functionality
• Mid-2022: Search themes introduced with 10-theme limit per asset group
• Late 2023: Search themes limit increased to 25 per asset group
• May 2, 2025: Search themes limit expanded to 50 per asset group, with phased rollout beginning