Consent Mode.

What is Consent Mode?

Consent Mode is a Google feature that tells Google tags, such as GA4 and Google Ads, whether a visitor has accepted or refused cookies, so the tags adjust their behaviour to match. It sits between your cookie banner and your tracking.

Version 2 added two signals, ad_user_data and ad_personalization, alongside the original ad_storage and analytics_storage. Together they cover whether personal data can be sent to Google for advertising and used for personalised ads.

Why it matters

Google's EU user consent policy covers visitors in the UK, the EEA and Switzerland, and Consent Mode is how your site tells Google that valid consent has been collected. Without the right signals, features that depend on user data, such as remarketing audiences and some conversion measurement, stop working properly for that traffic. The result is smaller audiences, patchier conversion data and automated bidding working from less information, which usually means paying more for the same results.

How it works

• Your banner records the choice A consent management platform shows the cookie banner and records what each visitor agrees to.
• Tags read the signal The banner passes the four consent states to Google's tags, usually through Google Tag Manager, before any tracking fires.
• Basic implementation Google tags stay blocked until the visitor makes a choice. If they refuse, nothing is sent to Google at all.
• Advanced implementation Tags load straight away with consent set to denied and send cookieless pings until consent is given. Google uses those pings to model conversions it cannot observe directly.

What to do about it

Open your site in a private browser window, refuse cookies, and use Google's Tag Assistant to see whether Google tags still fire and which consent states they report. Confirm all four signals, including ad_user_data and ad_personalization, are being sent. Both GA4 and Google Ads show whether they are receiving consent signals, so check there too. If any of this is unclear, have the set-up audited before your next campaign goes live rather than after.