Consent Mode (Google): definition and how it works

Consent Mode sits between a consent banner and Google's tags. The banner records what the visitor agreed to. Consent Mode hands that decision to the Google tag, Google Tag Manager and the products behind them, which then decide what to store and what to send.

How it works

Consent Mode works with consent types, each set to granted or denied. The four that matter for marketing measurement are:

The page sets a default state before any Google tag fires, then sends an update when the visitor makes a choice in the banner. A typical gtag.js default for EEA visitors looks like this:

window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('consent', 'default', {
  'ad_storage': 'denied',
  'analytics_storage': 'denied',
  'ad_user_data': 'denied',
  'ad_personalization': 'denied'
});

There are two ways to implement it:

• Basic: Google tags do not load until the visitor interacts with the banner and grants consent. Nothing is sent to Google for visitors who decline.
• Advanced: Google tags load straight away with denied defaults. While consent is denied, they set no cookies and send cookieless pings, which Google describes as carrying coarse information such as user agent, screen resolution and IP address as part of normal HTTP communication. Google uses these pings for conversion and behavioural modelling, and states that advanced gives an advertiser-specific model rather than a general one.

Why it matters in 2026

Google added ad_user_data and ad_personalization in late 2023 and, from March 2024, required advertisers who serve ads to users in the EEA to pass consent signals if they want to keep using features such as personalised advertising and audience lists for those users. Without ad_user_data granted, hashed data from enhanced conversions cannot be used for that user.

The practical result: a broken Consent Mode setup does not just lose data, it can quietly switch off remarketing and weaken bidding signals in Google Ads. With Google tag and Tag Manager settings changing in 2026 (see what Destinations change in your container), consent configuration is worth re-checking after any container restructure.

How to check it

1. Open Tag Assistant and connect to the page in a fresh browser session.
2. Select the first event and open the Consent tab. The On-page Default column should show all four types as denied for EEA traffic (or whatever your policy requires).
3. Accept the banner, then check the On-page Update column. It should show granted for the types the visitor accepted.
4. Repeat with "reject all" and confirm the update stays denied.
5. In GTM, use Admin > Container settings > Enable consent overview and review which tags have built-in or additional consent checks.

Our Consent Mode v2 checklist goes through each check in more detail.

Common mistakes

• Default set too late. If the default command runs after the Google tag, the first hits go out without a consent state.
• Banner and Consent Mode disagree. The CMP shows "rejected" but sends a granted update, or vice versa.
• Only two of four types. Older setups send ad_storage and analytics_storage but not ad_user_data and ad_personalization.
• Region rules wrong. A default meant for the EEA applies everywhere, or not at all, because the region parameter is misconfigured.
• Non-Google tags ignored. Consent Mode only governs Google tags. Meta, LinkedIn and others still need their own consent triggers.

Related terms: dataLayer, server-side tagging, Measurement Protocol.