Web and product analytics
Google Consent Mode v2 explained: basic vs advanced
The short answer
Consent Mode v2 is how your site tells Google tags whether a visitor agreed to analytics and advertising cookies, using four signals: ad_storage, analytics_storage, ad_user_data and ad_personalization. Google requires it for visitors in the EEA and UK if you use Google Ads measurement or personalisation. In basic mode no Google tag loads until the visitor agrees; in advanced mode tags load with consent denied and send cookieless pings that Google uses for modelling.
Key takeaways
- Four signals: analytics_storage, ad_storage, ad_user_data and ad_personalization.
- Basic mode loads nothing before consent; advanced mode sends cookieless pings that Google models from.
- Modelling needs roughly 1,000 consented daily users, so small sites mostly just lose the declined visits.
On this page 8 sections
The four signals
| Signal | Controls | Added |
|---|---|---|
| analytics_storage | Cookies for analytics, such as GA4's _ga | Original consent mode |
| ad_storage | Cookies for advertising, such as conversion linker cookies | Original consent mode |
| ad_user_data | Whether user data may be sent to Google for advertising | v2 (late 2023) |
| ad_personalization | Whether data may be used for remarketing and personalised ads | v2 (late 2023) |
A consent banner (your own, or a consent management platform) sets defaults before any tag fires, usually denied for EEA and UK visitors, and sends an update when the visitor chooses.
When it is required
Google's EU user consent policy requires advertisers who use Google Ads measurement, remarketing or personalisation for users in the EEA and UK to collect consent and pass it through consent mode. Google began enforcing the v2 signals in March 2024, alongside the EU Digital Markets Act. Without them, audiences and conversion measurement for those users degrade. Outside Europe, consent mode is optional for Google, but US state privacy laws (California's CCPA/CPRA and others) bring their own opt-out duties, including honouring Global Privacy Control in California.
Basic mode vs advanced mode
| Basic | Advanced | |
|---|---|---|
| Google tag loads before consent | No | Yes, with consent denied |
| Data sent if the visitor declines | None | Cookieless pings (no cookies, but the request still reaches Google) |
| Modelling of lost conversions and behaviour | General modelling only | Advertiser-specific modelling, if traffic thresholds are met |
| Privacy posture | Stricter: nothing reaches Google without consent | Weaker: Google receives pings, including the IP address in transit |
Many European regulators and privacy lawyers prefer basic mode, because advanced mode still sends a request to Google before consent. Advanced mode recovers more measurement. Which is right for you is a legal judgement for your jurisdiction, not a technical one.
What modelling can and cannot do
Behavioural modelling in GA4 fills gaps left by visitors who declined, using patterns from those who agreed. It only switches on for properties that meet Google's thresholds: at the time of writing, at least 1,000 events a day with analytics_storage denied for at least 7 days, and at least 1,000 daily users with analytics_storage granted for at least 7 of the previous 28 days. Smaller sites usually do not qualify, so for them a decline simply means fewer recorded visits.
Implementation checklist
- Set consent defaults in the page head, before the Google tag or GTM container loads.
- Scope defaults by region if your audience is international: denied for the EEA, UK and Switzerland, and whatever your lawyer advises elsewhere.
- Send a consent update when the visitor chooses, and again when they change their mind from a link in your footer.
- Treat a Global Privacy Control signal as an opt-out where state law requires it.
- Check with Tag Assistant that tags respect the state: with consent denied there should be no _ga cookie.
- Write your privacy policy to match what the site actually does, naming the cookies.
If consent losses make GA4 too thin
A cookieless analytics tool can count visits without a banner in many jurisdictions, and a lead tracking platform records each call or form lead directly, so you still know which campaign produced it. See GA4 alternatives.
Questions
- Is Consent Mode v2 mandatory?
- Google requires it for advertisers using Google Ads measurement or personalisation for EEA and UK users, enforced from March 2024. It is not a legal requirement in itself: the legal requirement is consent under EU and UK privacy law, and consent mode is how you pass that consent to Google.
- Does advanced consent mode send data when a visitor declines?
- Yes. In advanced mode Google tags load and send cookieless pings with consent marked as denied. No analytics or advertising cookies are set, but a request still reaches Google. In basic mode nothing is sent until the visitor agrees.
- Will consent mode recover all my lost data?
- No. GA4 behavioural modelling only runs for properties that meet Google's traffic thresholds (about 1,000 consented daily users and 1,000 denied daily events), and it estimates aggregates rather than recovering individual visits.
Sources
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