Click ID
Data & TrackingAlso: GCLID · FBCLID · MSCLKID · Google Click Identifier
Quick definition
Click ID is a unique string of characters that ad platforms attach to the end of a link when someone clicks an ad. Google's version is GCLID, Meta's is FBCLID, Microsoft's is MSCLKID. Your site's analytics tool reads that string to match the visit back to the exact ad that caused it.
How it varies across Australia
Click ID capture reliability varies sharply by tagging maturity across Australian advertisers. Businesses running server-side tagging keep click IDs consistently, while sites relying on client-side tags alone lose more to browser blocking and consent banners. The gap widens as privacy rules tighten.
See data and tracking scores across Australian industries →What it actually means
A click ID works like a coat check ticket. When someone clicks your ad, the ad platform staples a ticket number to the end of the destination URL before sending the visitor to your site. Google calls this ticket GCLID (Google Click Identifier). Meta calls its version FBCLID. Microsoft Advertising calls its MSCLKID. Different names, same job.
Your website's tag, usually the Google tag or the Meta pixel, reads that ticket number and stores it, often in a cookie or passed through to your CRM. Later, when that visitor converts, the platform can match the conversion back to the exact click that produced it. This is what powers conversion tracking and much of attribution reporting.
The problem is fragility. Browsers strip URL parameters, ad blockers remove them, cookie consent banners block the storage step, and privacy-focused browsers clear them fast. Every broken link in that chain is a conversion that happens but never gets reported. That's a meaningful chunk of the gap between what your CRM shows and what the ad platform reports.
Server-side tagging and first-party data capture close some of that gap. But the click ID itself remains a fragile piece of plumbing, not a permanent record.
A click ID is a receipt for a single ad click. Lose it, and the platform can't prove the click happened at all.
How it shows up
Click ID shows up in your URL bar as a long string appended after a question mark, something like gclid=Cj0KCQiA. It shows up in Google Tag Manager as a variable your tags reference. It shows up in your CRM as a hidden field captured on form submission. And it shows up as the reason your ad platform's conversion count doesn't match your CRM's lead count. When a business complains that a platform reports more conversions than sales can find, a missing or mismatched click ID is usually part of the story.
The Australian context
Australia's tightening privacy environment makes click ID capture harder than it used to be. Cookie consent banners, increasingly common on Australian sites ahead of expected Privacy Act reforms, can block the script that stores the click ID before the visitor even lands on the page.
Google's Consent Mode tries to fill some of that gap by modelling conversions when consent is denied, but modelled data is an estimate, not a captured click ID. Australian businesses running paid media without Consent Mode configured correctly are quietly losing conversion data and won't see it flagged anywhere. They'll just see a lower conversion count than reality.
Where people get this wrong
Related terms
Common questions
What does GCLID stand for?
GCLID stands for Google Click Identifier. It's the click ID Google Ads attaches to your ad's destination URL when someone clicks. Capturing it lets you import offline conversions back into Google Ads so the platform can optimise bidding against real outcomes, not just on-site actions.
Why is my click ID missing from some visits?
Ad blockers, browser privacy settings, redirect chains that drop URL parameters and cookie consent banners can all strip or block a click ID before your site stores it. It's rarely one cause. Check your tag manager's data layer against actual URL parameters to find where it's breaking.
Do I need to capture click ID manually?
Not usually. Google Tag Manager, most CRMs and platform-provided tracking snippets can capture click ID automatically if configured correctly. Manual capture matters most for offline conversion imports, like matching a phone lead back to the ad click that generated it.
Is click ID the same as a cookie?
No. A click ID is a value in a URL. A cookie is one common place to store that value once captured. You can lose the click ID even if cookies are enabled if the parameter never survives the redirect to your landing page.
Debrief
Get the next one
No spam. No fluff. Just the next article, straight to your inbox.
Keep exploring
About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
How we think →