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Consent Mode

October 27, 2026

Google Consent Mode is the mechanism that lets Google tags receive each user’s cookie consent choice from your cookie banner and change how they measure: users who accept are measured in full, users who decline get no advertising or analytics cookies. Consent Mode does not create a banner; it reads the choice made on your own banner (Google Ads Help, About consent mode, accessed October 2026).

What is consent mode? Consent Mode v2 consent types

Four consent types cover advertising and measurement, each either granted or denied:

Consent type What it controls
ad_storage Storage such as cookies (web) or device identifiers (apps) for advertising
analytics_storage Storage such as cookies or identifiers for analytics
ad_user_data Sending user data to Google for advertising
ad_personalization Personalized advertising

Source: Google Tag Platform, Consent mode overview, accessed October 2026. Google added ad_user_data and ad_personalization in November 2023, so the version with all four types is known as Consent Mode v2 (Google Tag Platform, Set up consent mode on websites, accessed October 2026).

Basic vs advanced consent mode

Basic Advanced
When Google tags load After the user interacts with the banner As soon as the page opens, with the default state you set (usually denied)
When the user declines Nothing is sent, not even the consent status Consent state and cookieless pings are sent
Conversion modeling General model Advertiser-specific model

Cookieless pings carry only details such as a timestamp, the referrer, whether the URL had a GCLID, and the consent state. Google says these pings are never used to track individual users across sites, build remarketing lists or create user profiles (Google Ads Help, About consent mode modeling, accessed October 2026).

Consent mode and conversion modeling

When a user declines cookies, Google Ads can no longer tie their ad click to their conversion. Conversion modeling learns from consented users and cookieless pings to estimate the missing part, then adds it to the Conversions column. For how measurement works with fewer cookies, see server-side tracking and marketing analytics.

Consent mode in Vietnam after Law 91/2025/QH15

Vietnam’s Personal Data Protection Law, No. 91/2025/QH15, took effect on January 1, 2026. Article 9 states that silence or no response does not count as consent. Article 28 says behavioral, targeted or personalized advertising may collect personal data by tracking websites and apps only with the user’s consent, and must give users a way to refuse (Law 91/2025/QH15, Articles 9 and 28, accessed October 2026). That is why more Vietnamese websites now show cookie banners with a reject button.

The law does not mention Consent Mode, and the tool does not replace collecting consent the way the law requires. Forms, pixels and penalties are covered in our guide to Vietnam’s personal data protection law for marketers.

Example: a cookie banner without consent mode (hypothetical)

A shop spends VND 54 million a month on Google Ads and records 240 conversions, a CPA of VND 225,000. It adds a banner that blocks Google tags for users who decline, but does not set up Consent Mode. 40% of visitors decline. Google Ads now records 180 conversions and reported CPA rises to VND 300,000, while real orders have not dropped.

Conversions fall by 25%, less than the decline rate, because Google reports that consented users are typically 2 to 5 times more likely to convert than unconsented users. With a target CPA of VND 250,000, Smart Bidding sees the campaign as over target and may lower bids.

Frequently asked questions

Is Consent Mode v2 mandatory in Vietnam?

Law 91/2025/QH15 does not name any tool. The obligation is to obtain and respect consent; Consent Mode helps Google tags act on that choice.

How long before you see the impact?

After at least 7 full days, Google Ads and Google Analytics may have enough data to report the uplift from Consent Mode, shown only when it meets a minimum data threshold.

If you already use Conversions API, do you still need Consent Mode?

Yes. Conversions API (CAPI) is how Meta receives events from your server, while Consent Mode controls Google tags. CAPI is not exempt from consent either. Form and CRM data is first-party data and should also be used for ads only when the customer has agreed.

If you want to check whether your cookie banner, Consent Mode and Google Ads conversions line up, contact Adtek.

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