Click ID

Updated 2026-11-02

Definition

A click ID is a unique value that an ad platform adds to the destination URL when someone clicks an ad. Google Ads adds gclid, Meta adds fbclid, and Microsoft Ads adds msclkid.

The URL ends up looking like https://example.com/pricing?gclid=Cj0KCQ.... The value identifies one click. Ad platforms use it to tie later conversions back to that click.

Example

This example uses made-up numbers. You run Google Ads but forget to add UTM tags. In one month, 3,000 clicks land on your site with a gclid.

Without reading click IDs, a tool sees a referrer of google.com and files all 3,000 under organic search. Your search channel looks strong, and your paid channel looks empty. If those clicks produced $15,000 in revenue, you'd credit it to SEO and might cut the ads that earned it.

A tool that reads click IDs puts those visits in paid search, even with no UTM tags.

Limits

Click IDs identify the click, and on their own they don't tell you the campaign. Getting campaign names from a click ID requires the ad platform's data. Some browsers also strip certain click IDs from links. So use UTM tags as well.

How Headstream measures it

Headstream looks for eight click IDs: gclid, gbraid, wbraid, msclkid, fbclid, ttclid, li_fat_id and twclid. The first four mark a visit as paid search, and the others mark it as paid social. This check runs first, so it beats UTM parameters and the referrer.

The click ID type and value are stored with the event and appear in your raw export. Headstream doesn't import ad spend or campaign data from ad platforms, so use utm_campaign for campaign names. See the methodology page.