Google Click Identifier (GCLID)

The Google Click Identifier, or GCLID, is an identifier associated with an eligible Google Ads interaction. With auto-tagging, a value may appear in the landing URL as a gclid query parameter. It helps supported Google Ads measurement systems connect later conversion activity with an advertising interaction under their attribution and data-processing rules.

A GCLID is not a promise that every visitor can be identified or that every click will result in an attributable conversion. Redirects, form handling, consent restrictions, browser behavior and integrations can affect whether the parameter is captured and usable. Do not assume that an identifier can be stored or joined with personal information without appropriate governance.

For eligible offline conversion workflows, systems may need to preserve identifiers and other required fields before an eventual outcome is uploaded. Teams should validate supported import methods and retention requirements rather than relying on a spreadsheet of anonymous-looking URL parameters as a complete tracking solution.