Where can you use custom segments in Google Ads?

By: Jyll Saskin Gales, Google Ads Coach

The rules for audience targeting in Google Ads can feel inconsistent and confusing, especially when it comes to Custom Segments. You’ve built the perfect audience - a combination of search terms, website visitors, and app users - only to find you can’t apply it to the campaign you’re running.

Let's clear up the confusion once and for all. This guide will provide a definitive, campaign-by-campaign breakdown of where and how you can use the functionality of Custom Segments.

Custom segments are not compatible with Search campaigns

Let's start with the most common question: Can you add a Custom Segment to a Search campaign?

The short answer is no. While Combined Segments are compatible with Search, Custom Segments are not.

Where Custom Segments Shine: Display & Demand Gen

Display and Demand Gen campaigns are the natural home for Custom Segments. These campaign types are designed to reach users as they browse content across the web, making them a perfect fit for audiences built on interests and behaviors.

• How they work: You can use a full Custom Segment - built from interests, search terms, websites, or apps - for your inclusion targeting.
• The Limitation: You cannot use Custom Segments for audience exclusions in these (or any) campaign types.

The Nuance for Video Campaigns: Meet the "Cousins"

This is where things get interesting. While you cannot apply a standard Custom Segment to a Video campaign, you use its building blocks, which are split into two distinct audience types:

1. "Custom Interests": This is essentially a Custom Segment without the search terms. You can build a powerful audience profile based on users' general interests, the types of websites they visit, and the types of apps they use.
2. "Custom Search Terms": This is a unique feature available specifically for Video campaigns. It allows you to target users on YouTube based on the things they have recently searched for on Google.

Note that if you add both Custom Interest and a Custom Search Term to a Video campaign, they will have an "OR" relationship since they are both audience targeting.

The Signal for Performance Max: Guiding the AI

Performance Max operates differently. You don't choose your targeting; you provide "audience signals" to guide the AI. Here, you also use relatives of Custom Segments:

• For Interest & Behaviour Signals: You can add a "Custom Interest" segment (interests, websites, apps) to your audience signals to give the AI a starting point for finding your ideal customer.
• For Search Intent Signals: To incorporate search intent, you don't use a segment. Instead, you use "Search Themes" within your asset group. This feature allows you to provide keywords that guide PMax in matching your ads to user queries.

Your Quick-Reference Custom Segments Compatibility Cheat Sheet

To pull it all together, here’s a simple breakdown of where Custom Segments are compatible:

• Search Campaigns: No. Use keywords for primary targeting.
• Display Campaigns: Yes. Use Custom Segments for inclusion targeting.
• Demand Gen Campaigns: Yes. Use Custom Segments for inclusion targeting.
• Video Campaigns: No, but you can use "Custom Interests" and/or "Custom Search Terms."
• Performance Max: No, you can use "Custom Interests" and/or "Search Themes" as signals.

Understanding these distinctions is key to building effective, efficient campaigns. For a quick-reference version of this guide and more, you can find handy cheat sheets in my book that lay out exactly which audience segments work with which campaign types, saving you time and headaches.

Find Inside Google Ads: Everything you need to know about Audience Targeting on Amazon, Google Play or Kobo.