Google Click ID (GCLID)
The GCLID is a unique ID Google Ads adds to your landing page URL on each ad click, so a later conversion can be tied back to that click.
In the platformMeasurement
GCLID
The GCLID is a unique ID Google Ads adds to your landing page URL on each ad click, so a later conversion can be tied back to that click.
Google Ads adds it as ?gclid=… when someone clicks an ad and auto-tagging is on. It is how Google links a sale or lead back to the exact click, campaign and keyword. On iOS traffic, Google may send gbraid or wbraid instead, which carry grouped, privacy-preserving click information. If the ID is stripped before your site or CRM can store it, the conversion still happens, but Google can't credit it, and bidding learns from less data.
Where you'll see it
In Google Ads, auto-tagging is under Admin > Account settings > Auto-tagging. You'll see the parameter in your browser's address bar after clicking an ad, and in Google Analytics as "google / cpc" traffic. For offline conversion imports, the GCLID is the field you store in your CRM. Meta uses fbclid and TikTok uses ttclid for a similar purpose.
Worked exampleA clinic's CRM leads
The clinic imports 60 qualified leads a month back to Google Ads, valued at $150 each. Redirects on the site drop the GCLID for 15 of them.
- Matched value = (60 − 15) × $150 = $6,750 instead of $9,000
- Missing value = 15 × $150 = $2,250 a month that Smart Bidding never sees
Keep the click ID
- Auto-tagging is on.
- No redirect or form plugin strips URL parameters.
- A hidden form field saves the GCLID, so offline imports can match.
- You handle
gbraidandwbraid; not every Google click carries a GCLID. - UTMs run alongside the GCLID, not instead of it. They serve analytics, not Google's conversion matching.