Google Ads Auto-Tagging: GCLID, GBRAID and UTM Tags Together

This guide uses Google Ads Help: About auto-tagging, Google Click Identifier (GCLID): Definition, Updates to iOS 14 campaign measurement and How Google Ads tracks website conversions; and Analytics Help: Benefits of Google Ads auto-tagging, Check if Google Ads auto-tagging works, Updates to iOS 14+ campaign measurement and Clicks and Sessions Discrepancy. Quotes are from those pages; other sources are linked where they are used.

What auto-tagging does

Auto-tagging is an account setting in Google Ads. Google's definition says it "automatically adds a parameter to your URLs to help you track offline conversions and report on your ad performance". The parameter is the Google Click Identifier, or GCLID. After someone clicks your ad, the landing page address gets an extra value; Google's example is www.example.com/?gclid=123xyz.

Google lists four jobs that need it:

• tracking conversions on your website "on all browsers";
• importing key event data into Google Ads from Google Analytics and other sources such as your CRM;
• importing Google Ads campaign and cost data into Google Analytics reports;
• importing Google Analytics engagement metrics into Google Ads reports.

The GCLID definition page adds that it is "required for Google Ads website conversion tracking". Auto-tagging is on by default for new accounts. Google also notes that the GCLID is sometimes created when the ad is shown rather than when it is clicked; if the same person clicks that ad again, the same GCLID is reused.

One exception: Google's page says "App campaigns don't respect auto-tagging features."

GCLID, GBRAID and WBRAID

Since Apple's App Tracking Transparency rules took effect on April 26, 2021, Google says it no longer sends the GCLID for iOS 14 traffic from ads in "a handful of Google apps". For that traffic, {gclid} is left empty and two other parameters can appear instead. Google Ads Help says most advertisers will not be affected.

Google's GBRAID page says it "measures conversions in a non-unique fashion (like Campaign ID)" without linking them to individual users, and that it "is case sensitive and shouldn't be converted to upper or lower case". You don't switch these on separately: they come with auto-tagging, so the same site requirements apply. For iOS, Google asks advertisers to have the Google tag set up correctly and says a small percentage "may need to allow arbitrary URL parameters".

Turning it on and checking it

The steps in Google Ads Help:

1. In your Google Ads account, click the Admin icon.
2. Click Account settings.
3. Open the Auto-tagging section.
4. Check or uncheck the box next to "Tag the URL that people click through from my ad".
5. Click Save.

It may already be on without you doing anything. Google says that when you create a new key event action, auto-tagging is activated automatically, unless you use cross-account conversion tracking. In that case you need to turn it on in each client account yourself. When you link Google Ads to Analytics, the link setup offers an Enable Auto-Tagging option. If you link a manager account with that option on, Analytics Help says auto-tagging "will be enabled on all Google Ads accounts directly linked to the manager account".

Does your site keep the parameter?

Auto-tagging only works if the click ID survives until your tags read it. Google's About auto-tagging page warns that "a small percentage of websites don't allow arbitrary URL parameters and serve an error page when auto-tagging is turned on". In that case Google says to turn auto-tagging off, ask your developer to allow arbitrary parameters, then turn it back on.

Analytics Help gives a manual test you can do before or after switching it on:

1. Open Chrome Developer Tools and the Network tab before loading the page.
2. Take your final URL and add a test value, such as ?gclid=TeSter-123. If the URL already has a ?, use &gclid=TeSter-123. If it has a #, put the parameter before the #.
3. Load the page and check the parameter is still in the address and in the Analytics requests once the page has fully loaded.

The common reasons it gets lost, from the same page:

• Redirects. A 301 or 302 that drops the query string loses the GCLID. Point the ad at the final page, or set the redirect to carry query parameters across. The discrepancy troubleshooter also says to "Ensure your Google Tag (for Google Analytics) fires before any redirects occur." Our redirects guide covers setting them up.
• Case changes. If a rewrite rule lowercases URLs, Analytics still sees the visit as google / cpc, but campaign, ad group and keyword show as (not set). Google says to allow uppercase characters, hyphens and underscores.
• Length. Make sure logs, storage and redirects can handle a GCLID of up to 100 characters. Google gives a long test value on its page for this.
• Frames. A tag inside an iframe can't read the parent page's address, so install Analytics on the parent page.
• Click trackers and other domains. Google Ads Help says click trackers and server-side redirects must pass the GCLID to the landing page, and if the conversion page is on a different domain, use the Google tag's domain linker to pass it on. See our cross-domain tracking guide.

Auto-tagging and UTM tags together

Auto-tagging and manual UTM tags can sit on the same URL, but Google Analytics 4 does not treat them as equals. Analytics Help says: "If you use manual tagging and auto tagging together, then the source, medium, and other traffic-classification dimensions use the auto-tagged values." Only utm_content and utm_term still show, in the Manual Ad Content and Manual Term dimensions. Google Ads Help puts it more directly: in GA4, "auto-tagging is prioritized over manual tagging due to the absence of an override option".

So for Google Ads traffic, UTM tags don't change how GA4 classifies the session. Google recommends auto-tagging over manual tags and lists what it adds:

• importing Analytics key events into Google Ads;
• no need to tag every final URL by hand;
• no manual errors, for example utm_source=Google being different from utm_source=google;
• audiences built on Google Ads dimensions such as ad group;
• extra dimensions manual tags can't supply, including account name, ad group, ad network type, customer ID, keyword text and query, plus a Google Ads report in Acquisition.

There is one case where Google suggests adding UTM tags as well. When traffic arrives with GBRAID or WBRAID, Google Ads dimensions such as campaign can show as "(not set)" in Analytics. The troubleshooter says you can add UTM parameters "to be used as a fallback", and gives this example: ?utm_source=google&utm_medium=cpc&utm_campaign=DemandGenCampaignName. The tidy place for that is the account-level final URL suffix, explained in our tracking template and final URL suffix guide. For naming rules, see our UTM guide.

Auto-tagging and Google Analytics 4

Linking a GA4 property to Google Ads needs auto-tagging. The product linking page lists it as a requirement, alongside admin access to the Google Ads account. Two details from Analytics Help are worth knowing:

• Unlinked accounts still show up. If auto-tagging is on but the account isn't linked, Google Ads visits still appear as google / cpc (or with your UTM values), but without campaign data. Those clicks are also left out of Google paid channels attribution, according to the Campaigns and traffic sources page.
• iOS traffic uses modeled conversions. For traffic affected by the iOS changes, Analytics Help says GA4 reporting "will use modeled conversions".

For conversions, Google Ads Help adds that the GA4 tag "no longer preserves the GCLID in a cookie for Google Ads conversion tracking events". If you want to count GA4 key events in Google Ads, import them through the link. Otherwise use the Google Ads tag, which stores the click ID in first-party cookies on your domain. Our Google Ads conversion tracking guide covers both routes, and GA4 basics covers the property itself.

Offline conversions

Google says auto-tagging "is also required for businesses that want to track offline conversions". The usual method is to save the GCLID with each lead in your CRM and upload it with the sale later. Two limits from Google's offline import troubleshooting page: "We only keep the GCLID for 90 days", and processing "typically takes less than 12 hours, but can take up to 72 hours if you use GBRAID and WBRAID-keyed conversions". Our offline conversion import guide walks through the setup.

Why clicks and sessions differ

Auto-tagging doesn't make Google Ads clicks and GA4 sessions match. The Analytics troubleshooter lists several reasons:

• Someone clicks the ad and leaves before the tag runs, so the GCLID never reaches Analytics.
• Someone bookmarks a URL that still contains the GCLID. Analytics records those later visits as Google Ads, but Google Ads doesn't count or charge them.
• Someone returns directly later. Analytics reports that session under the last known campaign, so sessions can exceed clicks.
• If auto-tagging is off and the URLs have no manual tags, paid clicks may be attributed to Google organic.

Google Ads also removes invalid clicks from its click count, which Analytics doesn't do. Our invalid clicks guide explains that.

A short checklist

This is our suggestion, based on the Google pages above:

1. Confirm the Auto-tagging box is checked in every account, including client accounts under a manager.
2. Test a landing page with ?gclid=TeSter-123 and check it survives redirects, HTTPS and www rewrites, and lowercase rules.
3. Link Google Ads to your GA4 property, so you get campaign data and not just google / cpc.
4. If Google Ads campaigns show as (not set) in Analytics, add fallback UTM tags in the final URL suffix.
5. If you import offline sales, store the GCLID (and GBRAID or WBRAID, unchanged in case) with each lead, and upload within 90 days.

Frequently asked questions

Is auto-tagging on by default?

Yes for new accounts, per Google Ads Help. It is also switched on automatically when you create a new key event action, unless you use cross-account conversion tracking.

Do UTM tags override auto-tagging in GA4?

No. Analytics Help says that when both are used, source, medium and other traffic-classification dimensions use the auto-tagged values. Only utm_content and utm_term still appear, as Manual Ad Content and Manual Term.

Why does my site show an error when auto-tagging is on?

Some sites reject URL parameters they don't recognise. Google says to turn auto-tagging off, have your developer allow arbitrary URL parameters, then turn it back on.

What are GBRAID and WBRAID?

Click parameters Google introduced in 2021 for iOS traffic where the GCLID can't be used under Apple's App Tracking Transparency rules. They arrive with auto-tagging and are case sensitive.

Does auto-tagging work for App campaigns?

No. Google's About auto-tagging page says App campaigns don't respect auto-tagging features.

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