LinkCleanhttps://example.com/landing?gad_source=1&gad_campaignid=12345678&gclid=Cj0KCQ
After LinkCleanhttps://example.com/landing
gad_source
Ad-click identifiers · Google Ads · introduced ~2023 · Updated 2026-08-14
What is gad_source?
What gad_source encodes
Google's auto-tagging system gained a series of gad_* parameters in 2023 as part of the GA4 migration. gad_source is a small numeric code — typically a single digit — that identifies which Google Ads surface generated the click.
On its own gad_source carries less attribution power than gclid — but it's used in combination with gad_campaignid and the older gclid to disambiguate where a click came from when Google's downstream analytics joins the data.
The values — and why there is no official list
The values people encounter in the wild map like this: gad_source=1 is Search Ads, =2 is the Display Network, =3 is YouTube, =5 is Shopping. Higher values such as =4, =6 and =7 turn up in real URLs but have no settled public reading.
Google publishes no specification for gad_source. There is no official documentation page, no reference table, and no entry in the Google Ads API docs that defines what each number means. The mapping above is community observation — advertisers comparing the parameter against the campaign type they know they clicked — not a documented contract. That matters in two directions: the common low values are reliable enough to reason with, and any value you cannot account for is genuinely undocumented rather than something you have failed to find.
Because it is undocumented, the mapping is also not guaranteed to be stable. Google added the whole gad_* family without announcement in 2023 and can renumber or extend it the same way.
Why it appeared recently
GA4 deprecated some of the older referrer-driven source attribution that Universal Analytics relied on. To keep the source/medium dimension populated reliably in GA4, Google started adding gad_source + gad_campaignid to outbound clicks as supplementary first-party tags. They sit alongside the classic utm_* and gclid rather than replacing them.
How LinkClean removes it
Default-on. Same default-on treatment as the rest of the gad_* family. No legitimate non-tracking use of this exact name.
Frequently asked
Why did Google add gad_source if gclid already existed?
Because GA4 needed first-party source/medium signals that don't rely on the cookie or referrer plumbing Universal Analytics had used. gad_source + gad_campaignid are durable first-party tags that survive cookie restrictions.
What do the gad_source numeric values mean?
Google doesn't publish the mapping. Community observation pins the common values as 1 = Search Ads, 2 = Display Network, 3 = YouTube, 5 = Shopping; values like 4, 6 and 7 aren't reliably documented. The Google ad-click parameters overview covers the whole gad_* / gclid family.
Is there official Google documentation for gad_source?
No. There is no Google Ads help page, reference table or API entry that specifies gad_source or what its values mean — which is why every published mapping traces back to advertiser observation rather than to Google. If you are searching for the official spec, the accurate answer is that one does not exist.
What is the difference between gad_source and gad_campaignid?
They answer different questions about the same click. gad_source is a one-digit code for *which Google surface* the click came from (Search, Display, YouTube, Shopping); gad_campaignid is the numeric ID of *which campaign* it belonged to. Google's auto-tagging usually adds both together, alongside gclid.
Will removing gad_source affect what I see?
No. It's read by analytics scripts, not by the destination page.
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