What it is: Not a law in itself , it’s Google’s mechanism for receiving consent signals from a CMP. But it’s effectively required because of the EU’s Digital Markets Act (DMA), which designates Google as a “gatekeeper” platform that must obtain verifiable end-user consent before processing personal data for advertising. Google passes that obligation to its advertisers through Consent Mode v2.

Who needs it: Any site using Google Ads, Google Analytics 4, Google Tag Manager, AdSense, AdMob, or Floodlight that has visitors from the EEA, UK, or Switzerland. As of October 2025, Google’s systems also accept TCF v2.3 strings in addition to Consent Mode v2 signals.

When it became mandatory: March 2024.

Why it matters: Without Consent Mode v2 properly configured, Google Ads conversion tracking, audience features, remarketing, Performance Max audience insights, and Smart Bidding optimization all degrade or fail for EEA/UK visitors. Conversion modeling , which can recover 30–50% of conversions lost to consent rejection , only works when consent signals are flowing correctly.

The four signals Consent Mode v2 sends:

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Basic vs. Advanced mode: - Basic Consent Mode , Google tags do not load at all until the visitor accepts. If they reject, no data flows to Google whatsoever. - Advanced Consent Mode (recommended) , Google tags load with denied defaults, then send anonymized “cookieless pings” so Google’s modeling can estimate behavior of rejecting users without storing any personal data. This typically recovers 15–25% of “lost” conversion data while remaining GDPR compliant.