Enhanced Conversions Google Ads: Step-by-Step Setup with GTM

Why Your Google Ads Conversions Are Underreported

With current tracking restrictions (ad blockers, ITP, consent refusals), Google Ads loses track of a significant portion of your conversions. The result: your campaigns appear less effective than they actually are, Smart Bidding algorithms optimize on incomplete data, and your budget decisions rest on truncated numbers.

Enhanced Conversions solve this by sending hashed first-party data (email, phone, name, address) to Google, which uses it to recover lost conversions via its user graph.

Measured impact: across the accounts we manage, enabling Enhanced Conversions generates an average of +5 to 15% additional attributed conversions, without changing your campaigns or budget.

How Enhanced Conversions Work

The Principle

1. A user converts on your site (purchase, form submission, signup)
2. Your site collects first-party data: email, phone, name, address
3. This data is hashed with SHA-256 (automatically by GTM)
4. Google compares it against its own user data (Google accounts)
5. If there is a match: the conversion is attributed to the campaign, even if the cookie has expired

Two Types of Enhanced Conversions

Type	Use Case	Required Data
Enhanced Conversions for Web	E-commerce, online forms	Email, phone, name, postal address
Enhanced Conversions for Leads	Lead generation, offline conversions	Email or phone (later CRM import)

Enhanced Conversions for Web covers the majority of cases: matching happens in real time at the moment of the online conversion.

Enhanced Conversions for Leads is complementary: it allows you to import offline conversions (contract signing, first payment) and tie them back to Google Ads clicks via the GCLID or user data.

Step-by-Step Setup with GTM

Step 1: Enable in Google Ads

First, enable the feature on the Google Ads side:

1. Google Ads > Goals > Conversions > Settings
2. Enhanced Conversions section > Turn on
3. Select Google Tag Manager as the implementation method
4. Accept the compliance terms

Important: without this activation on the Google Ads side, data sent by GTM will be ignored. This is the number one mistake.

Step 2: Prepare the DataLayer with User Data

On your confirmation page (purchase or form), push user data into the dataLayer:

// Place on the confirmation page, BEFORE the GTM container
dataLayer.push({
  event: "purchase",
  enhanced_conversion_data: {
    email: "marie.dupont@example.com",
    phone_number: "+33612345678",
    first_name: "Marie",
    last_name: "Dupont",
    home_address: {
      street: "15 rue de la Paix",
      city: "Paris",
      region: "Ile-de-France",
      postal_code: "75002",
      country: "FR"
    }
  },
  ecommerce: {
    transaction_id: "T-20260511-001",
    value: 249.90,
    currency: "EUR"
  }
});

Best practices for data:

• Email: lowercase, no spaces. This is the field with the highest match rate
• Phone: international format with country code (+33...)
• Name: lowercase, without unnecessary special characters
• Address: as complete as possible to improve matching

Step 3: Configure GTM Variables

In GTM, create Data Layer variables for each field:

GTM Variable	Data Layer Variable Name
dlv - ec_email	enhanced_conversion_data.email
dlv - ec_phone	enhanced_conversion_data.phone_number
dlv - ec_first_name	enhanced_conversion_data.first_name
dlv - ec_last_name	enhanced_conversion_data.last_name
dlv - ec_street	enhanced_conversion_data.home_address.street
dlv - ec_city	enhanced_conversion_data.home_address.city
dlv - ec_postal_code	enhanced_conversion_data.home_address.postal_code
dlv - ec_country	enhanced_conversion_data.home_address.country

Step 4: Configure the Google Ads Conversion Tag

1. Open your Google Ads Conversion Tracking tag
2. Check Include user-provided data from your website
3. Select Manual configuration (Data Layer)
4. Map each field with the variables created in Step 3:

Enhanced Conversions Field	GTM Variable
Email	{{dlv - ec_email}}
Phone Number	{{dlv - ec_phone}}
First Name	{{dlv - ec_first_name}}
Last Name	{{dlv - ec_last_name}}
Street	{{dlv - ec_street}}
City	{{dlv - ec_city}}
Postal Code	{{dlv - ec_postal_code}}
Country	{{dlv - ec_country}}

Step 5: Hashing Is Automatic

You do not need to hash the data yourself. GTM automatically handles SHA-256 hashing before sending. If you pre-hash server-side, make sure to check the corresponding option in the tag configuration.

SHA-256 hashing is irreversible: Google cannot read the email in plain text. It simply compares hashes against each other.

Step 6: Test with Tag Assistant

1. Launch GTM in Preview mode
2. Complete a test conversion
3. In Tag Assistant, click on the Google Ads conversion tag
4. Check the Enhanced Conversions tab: fields should appear with “Hashed” status
5. In Google Ads > Conversions > your conversion > Diagnostics: verify that Enhanced Conversions are detected

Note: it takes 48 to 72 hours after the first conversion for Google Ads to display Enhanced Conversions diagnostics.

Performance Impact: Real Data

Additional Conversions Recovered

Across a sample of 25 Google Ads accounts (budgets EUR 3K to EUR 150K/month), here are the results after enabling Enhanced Conversions:

Sector	Additional Conversions	Time to Impact
Fashion e-commerce	+12%	2-3 weeks
Tech e-commerce	+8%	2-3 weeks
B2B lead gen	+15%	3-4 weeks
Real estate lead gen	+11%	3-4 weeks
SaaS / subscription	+6%	2-3 weeks

Impact on Smart Bidding

More attributed conversions means a richer signal for automated bidding strategies (Target CPA, Target ROAS, Maximize Conversions). The algorithm learns on a more complete dataset, which translates to:

• Less fluctuation in bids
• Faster exits from learning phase for new campaigns
• Better budget allocation across campaigns

Common Mistakes to Avoid

1. Not Enabling in Google Ads Before Configuring GTM

The feature must be activated on both sides. Without the Google Ads activation, GTM sends data into the void.

2. Only Sending Email

Email alone provides a good match rate, but adding phone and name improves it significantly. The more fields you send, the more precise the matching.

3. Poorly Formatted Data

• Email with spaces: " marie@example.com " — hashing will produce a different result
• Phone without country code: 0612345678 instead of +33612345678
• Name with uppercase: DUPONT instead of dupont

GTM partially normalizes data, but it is best to clean it upstream.

4. Forgetting Consent

Enhanced Conversions are subject to GDPR. You can only send this data if the user has consented to advertising tracking. Ensure your CMP conditions the data sending on ad_user_data = granted.

5. Insufficient Testing

An error in variable mapping can go unnoticed for weeks. Test with Tag Assistant on every conversion type (purchase, form, signup).

Enhanced Conversions for Leads: The Bonus

If your model relies on lead generation with offline conversion (sales call, contract signing), also set up Enhanced Conversions for Leads:

1. Capture the GCLID in a hidden form field
2. Store it in your CRM alongside the lead data
3. Import offline conversions via the Google Ads API or CSV upload
4. Google matches via GCLID or hashed user data

This is the only way to give Google Ads visibility into your real conversions — the ones that generate revenue.

Take Action

Enhanced Conversions are one of the simplest and most impactful levers for improving your Google Ads performance. Setup takes hours, measurable impact comes within weeks.

At chillmetrics, we configure your Enhanced Conversions as part of our complete tracking installations. DataLayer, GTM, Google Ads, testing: everything is included.

Let us handle your tracking installation and recover the conversions Google Ads can no longer see.