Cross-domain google ads conversion tracking can easily be implemented using GTM for Google Ads. Cross-domain conversion happens when a user takes the final conversion action on a domain different to it landed on. For example, a user could land on a landing page on domain a.com and finally converts on domain b.com.
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How to Track Cross-Domain Google Ads Conversions
Before we implement Google ads cross-domain tracking here are some of the pre-requisite.
- You should have access to both of the domains or at least access to the landing page on domain a.com and thank you page or conversion page on b.com
- Both of the domains should have GTM code installed on them
Setup Google Ads Conversion Linker Tag

Google Ads Conversion linker for cross-domain ads conversion tracking
- Under Conversion Linker tag, select “Enable linking across domains”
- Under auto-link domains, input both of the domain separated by a comma
- URL position should be query parameter and,
- check “accept incoming linker parameters”
- And you are done.
How does cross-domain Google ads conversion work in Google Ads?
Google ads tracking is cookies based tracking. A cookie is a small piece of information different websites store in your web browser. When a user takes some action on your ad such as clicking the ad or watching a video, Google Ads will store cookies that contain information about the interaction. When someone converts on your website, the conversion tracking tag you installed reads this cookie and sends it back to Google Ads with the conversion information which reflects in your Google ads account.
Google Ads uses the first-party cookie to track the user activity such as user’s navigation across multiple pages on the same site. Thus, the first party cookies are limited to a website only. So, in case of cross-domain conversion, first-party cookies limited to the landing page domain only cannot track the actions which happen on other websites.
Track Cross-Domain Google Ads Conversions Using Analytics
You can also track Google ads conversion as a goal in Google analytics and later import that goal as a conversion in Google ads. Here are the pre-requisites for that:
- You need to implement cross-domain google analytics tracking across both of the domains. Here is my blog on implementing subdomain Google Analytics Tracking across domains using GTM. The concept is the same for sub-domain and cross-domain.
- Create a Goal in the Google Analytics accounts for users who visit the thank you page on the second domain.
- Import that goal as a conversion in google ads account. For that, Google ads account and Google Analytics account should be connected.
This is VERY helpful! Question… In the first section, when you mention “both of the domains should have GTM installed on them” do you mean that domain a.com and b.com should have the SAME GTM tag? Or does a.com have it’s own GTM tag and b.com has it’s own tag and then setup cross domain linking in both individual GTM accounts? Or is this all in one GTM container? Thanks so much.
a.com and b.com both should have the same GTM tag
Thank you. Saved me big time