Consent Mode v2 and enhanced conversions in the EU: a practical guide

If you advertise on Google Ads with European traffic, two pieces decide how many conversions you see and how well the system bids: consent mode (Consent Mode v2) and enhanced conversions. The first tells Google what each user has agreed to; the second recovers conversions by sending your own hashed data. This guide explains what each does, according to the official documentation, and in which order to implement them.

Google's consent policy in Europe

Google's EU user consent policy applies to users in the European Economic Area, the UK and Switzerland. It requires obtaining consent where the law requires it, keeping records of consent and giving users clear instructions to revoke it. Consent mode is the technical mechanism that passes those choices to Google's tags.

Consent mode: basic or advanced

The Google Ads help distinguishes two implementations:

The version 2 parameters

On top of ad_storage and analytics_storage, version 2 adds ad_user_data (consent to send user data to Google for advertising) and ad_personalization (consent to personalised advertising, such as remarketing). The developer guide also documents the region parameter (ISO 3166-2 codes, to apply different defaults per country), wait_for_update, ads_data_redaction and url_passthrough.

• wait_for_update: how many milliseconds to wait for the CMP to send the choice before tags fire.
• ads_data_redaction: with ad_storage denied, strips ad click identifiers from pings.
• url_passthrough: passes click parameters through the URL across pages when there are no cookies.

Enhanced conversions

Enhanced conversions supplement your tags by sending first-party conversion data (such as the email address) hashed with SHA256 before it leaves for Google, which matches it against signed-in Google accounts to attribute conversions that would otherwise be lost. There are two variants:

• For web: improves measurement of conversions on your site (purchases, sign-ups).
• For leads: measures sales that close offline from leads captured on your site.

If you use Google tag gateway or server-side Google Tag Manager, the official help says the data is also encrypted in transit.

Recommended implementation order

1. A certified CMP and a banner with accept and reject at the same level.
2. Defaults set to denied for the regions that require it, using region if you run several markets.
3. Consent update when the user decides, including all four parameters.
4. Testing with Tag Manager preview mode or Tag Assistant.
5. Enhanced conversions, once consent works.
6. Impact review: Google says consent mode results show after at least 7 days.

Common mistakes

• A banner that fires tags before any choice is made.
• Only ad_storage and analytics_storage are updated and the two v2 parameters are missing.
• Enhanced conversion data not normalised (spaces, capitals) before hashing.
• Comparing conversions before and after without waiting for modelling.