What Google Consent Mode Is
Google Consent Mode is a set of signals that tell Google's products what a user has agreed to. It does not show a consent prompt itself. Your consent management platform or your own code collects the user's choice, then sets Consent Mode values. Google Analytics, Google Ads, Floodlight and the Firebase SDK read those values and change their behavior, collecting less or nothing when consent is denied.
The goal is a single, consistent consent signal across Google's measurement and advertising products, so advertisers can respect user choices without wiring each tag separately.
The Four Signals
Consent Mode v2 has four main parameters. ad_storage covers storage, such as cookies or app identifiers, used for advertising. analytics_storage covers storage used for analytics, such as visit duration. ad_user_data covers whether user data may be sent to Google for advertising purposes at all. ad_personalization covers whether data may be used to personalise ads, such as remarketing lists.
Each is set to granted or denied. Apps and sites usually set defaults before the consent prompt resolves, often denied for users in regions that require consent, and update them once the user decides.
Why v2 Became Required
Google introduced ad_user_data and ad_personalization in late 2023 as part of its compliance with the EU Digital Markets Act, which requires gatekeepers such as Google to obtain consent before combining personal data across services for advertising. From March 2024, Google required advertisers to send v2 signals for users in the EEA to keep using that data for measurement, audience building and personalisation. Without them, conversion tracking and remarketing for those users degrade.
Google also requires publishers serving its ads to users in the EEA, the UK and Switzerland to use a Google-certified CMP integrated with the IAB TCF. Certified CMPs can set Consent Mode values automatically from the user's TCF choices.
Basic vs Advanced Mode
In basic mode, Google tags are blocked until the user interacts with the consent prompt. If the user declines, nothing is sent. This is the most conservative setup, but it leaves no data for declined users, and Google models conversions only from general patterns.
In advanced mode, tags load immediately with consent denied by default. When consent is declined, they send cookieless pings that carry no identifiers, such as the fact that a conversion happened, which Google uses to model conversions more precisely. Advanced mode recovers more measurement but sends some data without consent, so decide on it with your legal team.
Consent Mode in Mobile Apps
In apps, consent is set through the Firebase SDK's setConsent method with the same consent types, or automatically by a CMP that supports it. Apps that use an MMP to send conversions to Google Ads need a second step: the MMP has to forward consent with each conversion, because Google receives the event from the MMP's servers rather than from the Firebase SDK.
Linkrunner supports Google consent signals for the Digital Markets Act, so conversions sent to Google Ads carry the user's consent state. Linkrunner's iOS SDK also reads TCF consent values. See Google and Meta ads for how Linkrunner works with Google Ads, and the Trust Center for its privacy posture.
Common Mistakes
The most frequent problem is setting consent after tags have already fired, which sends data before the user decided. Set defaults first, then update. Another is forgetting the two v2 signals, which leaves EEA measurement limited even when users consent. A third is applying EEA defaults everywhere or nowhere: use regional defaults so each user gets the treatment their location requires.
How Consent Mode Affects Your Numbers
Expect reported conversions in Google Ads to change when you implement Consent Mode correctly. Users who decline consent are no longer measured the same way, so observed conversions for EEA traffic drop. In advanced mode, Google adds modelled conversions to fill part of the gap, and those appear in reporting once your traffic meets Google's thresholds.
This affects bidding. Smart Bidding strategies learn from the conversions they see, so a sudden drop in observed conversions can change bids until the model adjusts. Plan the rollout outside major campaign launches, watch conversion volume by region, and compare against your MMP's install counts to understand how much of the change is consent rather than performance.
It also affects comparisons between tools. Your MMP, Google Ads and Google Analytics may each handle declined users differently, so their EEA numbers will diverge more than before. Document how each tool treats consent so campaign reviews compare like with like.