What Is gad_campaignid? Decode Google's Campaign ID

gad_campaignid shows up on links from Google ads, often beside gclid and gad_source. Paste the URL to see all three split apart and what each one identifies.

Example: https://example.com/foo?gclid=Cj0KCQjw8LqzBhDEARIsAA&gad_source=1&gad_campaignid=20406685129

A campaign ID, not a click ID

Google adds gad_campaignid to the final URL of clicks from its ads. Google says it identifies "the specific campaign that drove the click", and that "all conversions from the same campaign will have the same gad_campaignid." That second line is the difference from gclid. A gclid belongs to one click. A gad_campaignid is shared by every click on the campaign, so it says nothing about you.

Google groups it with gad_source as the gad_* parameters, which it describes as providing "aggregate data about your campaigns" without compromising user privacy.

What it is used for

On sites running a Google tag, the gad_* values are captured with conversion events automatically. The bigger use is offline conversion import, where a business uploads sales from its own records, such as a CRM, back into Google Ads. Google tells those advertisers to capture gad_* values from all landing pages and import them with their conversions, calling this "particularly important" when individual identifiers like gclid and user-provided data are not available. With the campaign ID attached, Google can still credit the sale to the right campaign.

Where it sits, and what breaks it

Google appends the gad_* parameters to the end of the final URL, before any # fragment. Its tags expect to find them as top-level parameters on the page where the tag loads, so a redirect that drops the query string loses gad_campaignid along with gclid and gad_source. A small share of sites serve an error page when a URL carries a parameter they do not recognize. Google's check is to add ?gad_source=1 to your landing page by hand and confirm the page loads with the parameter still in the address bar. Google also notes the parameter is case sensitive.

What removing it costs

The visitor sees no difference. It identifies a campaign, so deleting it from a link you share gains you no privacy. The cost falls on the advertiser: a conversion that reaches the tag without it loses its campaign-level context, and an offline import has one less way to find the right campaign.

Questions

What does gad_campaignid mean in a URL?

A parameter Google adds to the final URL of clicks from its ads, often next to gclid and gad_source. Google says it identifies "the specific campaign that drove the click."

Is gad_campaignid unique per click like gclid?

No. Google says all conversions from the same campaign have the same gad_campaignid, while a gclid belongs to one click, so it identifies a campaign and says nothing about the person.

What is gad_campaignid used for?

Crediting conversions to the right campaign. Google tags capture it with conversion events automatically, and Google tells advertisers who import offline sales, such as from a CRM, to capture gad_* values and import them, calling this "particularly important" when gclid and user-provided data are not available.

Decode a link with gad_campaignid in it