Conversion Linker (Google Tag Manager)

Set ad click information in first-party cookies

The Conversion Linker tag is used to store click data in first-party cookies associated with your domain. This functionality helps ensure that conversions are measured effectively. Deploy a Conversion Linker tag on any page where visitors may land after they click an ad or promotion.

When people click on your ads, the URL of the conversion page on your website typically includes information about the click. When a site visitor takes an action that you’ve tagged as a conversion (e.g. when a Google Ads conversion tracking tag is fired), the click information is used to associate that conversion with the click that brought the visitors to your site.

The Conversion Linker tag automatically detects the ad click information in your conversion page URLs, and stores this information in first-party cookies on your domain. If you use the Conversion Linker tag with Google Marketing Platform products, the Conversion Linker tag may also store unique identifiers in those cookies.

Basic setup

To set up a Conversion Linker tag:

  1. Click Tags New.
  2. Click Tag Configuration and select Conversion Linker.
  3. Select a trigger to fire your new Conversion Linker tag. In most cases, you should use a trigger that fires on all page views, or on specific page views where site visitors will land after an ad is clicked.
  4. Save and publish your tag configuration.


Enable linking across domains

Enable linking across domains if you have landing pages and conversion pages on more than one domain. When you select this option, hyperlinks that point to a linked domain will have a linker parameter appended to the URL. A destination domain with a compatible linker tag will check inbound URLs for linker parameters. If a valid linker parameter is found, a 1st party measurement cookie is extracted and stored. You can learn more here:

To configure the conversion linker tag to work with multiple domains:

  1. Select Enable linking across domains. This setting will enable this tag to handle incoming links that have a linker parameter.
  2. Optional, but recommended: In Auto Link Domains, enter a list of domains that should be linked with this tag. Any links that point to a domain listed in this field will have a linker parameter appended to the URL.
  3. Optional: To link forms, set Decorate Forms to true.

Optional: If you need to tell Google Tag Manager to read the unique parameter from a fragment (#) instead of a standard query (?), set URL Position to Fragment. Otherwise, leave this option set to the default Query Parameter option.

NOTE: Decorate Forms will only work in conjunction with the URL Position option set to Query Parameter. This is because some browsers strip off the URL fragment from form submissions.

Override cookie settings (advanced settings)

For most cases, the basic configuration of this tag will be sufficient. Only adjust the settings if you have a specific need that requires it.

You may need to override some cookie settings in cases where you already have cookies with the same names, you need to have multiple sets of cookies, or when you don’t want ad click info from one subdomain of your website to be available for conversions on another subdomain. For these cases, use the override cookie settings feature.

The Conversion Linker tag sets ad click information in cookies named _gcl_aw and _gcl_dc, and uses the top-most domain and root level path. If you need to override any of these settings, you can do so in Linker Options.

When you select the Override cookie settings checkbox, text fields for Name prefix, Domain, and Path will appear:

  • Name: This is the prefix used as part of the cookie names.The default prefix name is _gcl. For example, if you change the Name field to _gcl2, the Conversion Linker tag will set cookies named _gcl2_aw and _gcl2_dc. If you change the prefix of the cookie names, any tags that read ad click info from these cookies (e.g. Google Ads conversion tags) must also be configured to use the same prefix.
  • Domain: This is the domain of your website on which the first-party cookies should be set. By default, the Conversion Linker tag will use the highest level domain on which it can set cookies. For example, if your website address is, the Conversion Linker tag will set the cookie domain to Only set this field if you need to limit the cookies to a lower-level domain.
  • Path: This is the path used to set the cookies. By default, the cookie path will be the root level of the domain. Only set this field if you need to limit the cookies to a subdirectory of a domain.

You can also edit how tags work with first-party cookies set by Conversion Linker tags: These tags will offer two additional configuration options in the Conversion Linking section:

  • Enable Conversion Linking: By default, all tags that read data set by the Conversion Linker tag have "Enable Conversion Linking" set to true. Set this value to false if you need to disable the tag's ability to work with Conversion Linker tags.
  • Cookie Prefix: If you have changed the cookie name prefix in a Conversion Linker tag, add that same prefix here so that the tag can read data from the correct cookie.

If you haven't added Google Tag Manager to your pages yet, here's how you can do that:

Note: This article can also be found on the Google Help Center here: