Google Consent Mode v2
— Complete Guide 2026

What is Google Consent Mode v2?

Google Consent Mode is an API that acts as a bridge between your website's cookie consent banner and your Google tags (GA4, Google Ads, Floodlight). When a visitor accepts or declines cookies, your consent management platform communicates that decision to Google via four consent signal parameters — and Google's tags adjust their behaviour accordingly.

Version 2 was released in November 2023 and added two new parameters — ad_user_data and ad_personalization — required under the EU's Digital Markets Act. These two parameters, combined with the existing analytics_storage and ad_storage, must all be present for a v2-compliant implementation.

The four consent parameters — what each one controls

All four parameters must be present in your implementation. A banner that only sets analytics_storage and ad_storage is a v1 implementation — it will pass v1 checks but fail v2 compliance, silently.

Basic mode vs Advanced mode — which should you use?

This is the most consequential decision in your Consent Mode setup — and the one most commonly misunderstood. Both modes are GDPR-compliant. The difference is how much data you recover when users decline, and how accurately you can measure conversions.

How to implement Google Consent Mode v2 correctly

The order of operations matters critically here. The most common implementation error — responsible for the majority of the 67% of broken setups — is firing the consent default after Google tags have already loaded. This creates a race condition that makes the consent signal meaningless.

// Phase 1: Default — fires BEFORE any Google tag loads
window.dataLayer = window.dataLayer || [];
function gtag() { dataLayer.push(arguments); }

gtag('consent', 'default', {
  'analytics_storage':  'denied',
  'ad_storage':         'denied',
  'ad_user_data':       'denied',   // v2 — required
  'ad_personalization': 'denied',   // v2 — required
  'wait_for_update':    2000        // wait 2s for CMP to load
});

// Phase 2: Update — fires AFTER visitor interacts with banner
// Sent by your CMP when visitor accepts/declines
gtag('consent', 'update', {
  'analytics_storage':  'granted',  // or 'denied'
  'ad_storage':         'granted',
  'ad_user_data':       'granted',
  'ad_personalization': 'granted'
});

The 7 most common implementation errors

67% of Consent Mode setups have issues. Most are invisible until enforcement kicks in or data suddenly disappears. These are the failure patterns to check first.

Check if your Consent Mode v2 is configured correctly

Our free scanner checks your homepage for Google Consent Mode v2 configuration issues — including whether all four parameters are being set, whether they fire before Google tags load, and whether Google Analytics is collecting data before consent is given.

Google Consent Mode v2 checklist 2026

Click each item to mark as done. Use this to verify your implementation is complete.

• All four parameters present: analytics_storage, ad_storage, ad_user_data, ad_personalization
• Consent defaults set to denied before any Google tag or GTM container loads
• wait_for_update timeout added to consent default (2000ms recommended)
• Consent update command fires after visitor interacts with banner — not just on page load
• Region filtering applied — EEA/UK defaults separate from global defaults
• Consent decision persisted in first-party cookie — returning visitors not shown banner unnecessarily
• Basic or Advanced mode chosen and implemented consistently
• Verified in DevTools Network tab — gcs and gcd parameters reflect denied state when consent declined
• Google Tag Assistant confirms all four parameters are transmitting
• June 15, 2026 update reviewed — Google Signals retirement and ad_storage sole governing parameter understood
• Using a Google-certified CMP to handle signal transmission automatically

Google Consent Mode v2 — frequently asked questions