If you run Google Ads or use Google Analytics, you've probably heard of "Consent Mode v2", often from a developer, an agency or a warning in your Google account. It sounds technical, but the idea behind it is simple: it's how your website tells Google what each visitor has agreed to on your cookie banner, so Google's tags can behave accordingly.
Here's what it is, why it matters and how to check your own site, without the jargon.
What is Consent Mode?
Consent Mode is a feature built into Google's tags. In Google's own words, it "receives your users' consent choices from your cookie banner or widget and dynamically adapts the behaviour of Analytics, Ads and third-party tags that create or read cookies."
In other words, your cookie banner asks the question, and Consent Mode passes the answer on to Google. If a visitor says yes, Google's tags work as normal. If they say no, the tags hold back.
Google is clear about where responsibility sits. Its developer documentation says that you are responsible for obtaining users' consent, whether through a consent banner, a custom solution or a consent management platform (CMP). Consent Mode doesn't collect consent for you. It only communicates the choice.
What's new in version 2?
The original version of Consent Mode used two signals. Version 2 adds two more, as part of what Google describes as strengthening the enforcement of its EU user consent policy.
For visitors in the European Economic Area (EEA), Google says advertisers must collect consent and share consent signals with Google to keep using its tags for measurement, ad personalisation and remarketing.
What about the UK? Google's EU user consent policy covers users in the EEA, the UK and Switzerland. However, Google's policy help page also says it does not currently expect advertisers to send a verified consent signal for UK or Swiss traffic, and that this requirement applies to EEA traffic. In practice, many UK businesses have EEA visitors too, and the UK has its own consent rules under the UK GDPR and the Privacy and Electronic Communications Regulations (PECR). So setting up Consent Mode v2 properly is sensible for most UK advertisers, even where it isn't strictly enforced. This post isn't legal advice, so if you're unsure what applies to you, check with a data protection specialist.
The four signals, in plain English
Consent Mode v2 works with four main signals. Each one is set to either "granted" or "denied", based on the visitor's choice. Here is what each one does, according to Google's documentation:
- ad_storage controls whether advertising cookies can be stored on the visitor's device.
- analytics_storage controls whether analytics cookies can be stored, for example to measure visit duration.
- ad_user_data controls whether the visitor's data can be sent to Google for advertising purposes.
- ad_personalization controls whether the visitor's data can be used for personalised advertising, such as remarketing.
The two new signals are ad_user_data and ad_personalization. Google's consent mode reference notes that both need to be granted for personalised advertising to work in its advertising platforms.
Basic vs advanced mode
There are two ways to set up Consent Mode, and the difference matters for your reporting.
Basic mode blocks Google's tags completely until the visitor interacts with your cookie banner. If they decline, nothing is sent to Google at all, not even the fact that they declined.
Advanced mode loads Google's tags straight away, but in a restricted state until the visitor makes a choice. If they decline, Google's tags don't set cookies, but they do send what Google calls "cookieless pings". These are limited signals such as the consent status, the time, the browser type and whether the visit came from an ad click.
The trade-off is in the modelling. Google says advanced mode supports an "advertiser-specific" model for estimating conversions, while basic mode relies on a "general model". Advanced mode can give you a fuller picture, but some businesses prefer basic mode because nothing is sent before consent.
What happens when visitors say no?
When someone declines, consent-aware Google tags don't read or write the relevant cookies. Depending on the signal, that means:
- advertising cookies aren't stored or read
- analytics cookies aren't stored or read
- remarketing and personalised advertising don't receive that visitor's data
- personal data such as enhanced conversions data isn't used for advertising
You'll see fewer directly measured conversions and visits in your reports. To help fill the gap, Google uses the cookieless pings from advanced mode to model some of the missing conversions and behaviour in Google Ads and GA4. Google says this modelling only works once your site meets certain data thresholds. Google Ads may also show a consent mode "uplift" figure once it has at least seven full days of data and enough volume, so smaller sites may not see it at all.
How Consent Mode fits with your cookie banner
Your cookie banner or CMP and Consent Mode are two halves of the same job:
- Your banner or CMP asks the question and records the visitor's choice.
- Consent Mode passes that choice to Google, so its tags behave accordingly.
Google notes that many CMPs handle the second step for you, and it runs a CMP Partner Program, although it says you don't have to use a CMP from that list. If your banner is custom-built, someone needs to make sure it sends the consent state to Google correctly.
Consent Mode only governs Google's own tags. Other tags, such as Meta or LinkedIn pixels, need to be controlled separately, for example through consent settings in Google Tag Manager. If you're moving to server-side tracking, consent still applies there too. We cover that in why server-side tracking still needs consent. And for the wider changes to Google's tagging tools, see our round-up of the latest Google Tag Manager updates.
Your Consent Mode v2 checklist
Here's a practical checklist you can run through for your own site:
- Check your banner works. Visit your site in a private browser window and confirm the banner appears before any tracking starts.
- Confirm all four signals are sent. Ask your developer or agency to check that ad_storage, analytics_storage, ad_user_data and ad_personalization are all set. Google's Tag Assistant can help with this.
- Know which mode you're using. Find out whether you're on basic or advanced mode, and make sure it was a deliberate choice.
- Check your default settings. Make sure each signal starts in the right state before the visitor makes a choice.
- Test "reject all". Decline cookies and confirm that Google's tags hold back as expected.
- Test "accept all". Accept cookies and confirm that tracking works normally.
- Check your non-Google tags. Make sure Meta, LinkedIn and other pixels also respect the visitor's choice.
- Review your data uploads. If you upload customer lists or offline conversions to Google, check you also have consent for that data.
- Update your cookie and privacy policies so they accurately describe what you collect and who receives it.
- Recheck after any changes to your website, banner or tags.
Getting it right
Consent Mode v2 isn't something to fear, but it is something to get right.
If you'd like help checking your Consent Mode setup or reviewing your tracking more widely, take a look at our services and get in touch.
Sources: Google Ads Help, "About consent mode"; Google for Developers, "Consent mode overview"; Google Ads Help, "Updates to consent mode for traffic in the European Economic Area"; Google Ads Help, "Consent mode reference"; Google, "Help with the EU user consent policy".