Google Ads offline conversion tracking: how to set up

The challenges of tracking offline conversions in Google Ads

Tracking offline conversions is essential for measuring true return on ad spend (ROAS) in Google Ads. Advertisers typically care most about offline events—qualified leads, closed deals, or trials that convert to paid subscriptions—because these reflect actual business outcomes. Relying solely on lead conversions causes Google’s algorithms to optimize for lower-quality leads, since they lack visibility into which users ultimately become paying customers.

While Google Ads offers built-in method of tracking such conversions called Enhanced Conversions, match rates for offline conversions uploaded as enhanced conversions using email addresses or phone numbers can be relatively low—often around 40–50%—which leads to incomplete and inaccurate campaign performance data.

Why conversion match rates are poor with Enhanced Conversions uploads

The primary reason for low match rates is that uploaded customer data—such as email addresses or phone numbers—must exactly match the information in Google’s existing user profiles. Even minor discrepancies can lead to non-matches, skewing ROAS calculations and campaign attribution. As a result, optimization becomes more difficult, and efficient budget scaling is hindered, despite the effort invested in passing customer data from CRMs or automation tools like Zapier.

There are also significant operational challenges in ensuring that hashed lead information is consistently submitted to Google Ads. Because advertisers cannot see precisely which enhanced conversion data Google captures on their site, enhanced conversions for leads often serve as a helpful proxy for performance rather than a complete and reliable solution.

The Solution—match clicks to conversions at the time of website visit

The optimal way to upload offline conversions is to capture unique click identifiers, such as the Google Click Identifier (GCLID or WBRAID/GBRAID for IOS Google apps), at the time of the website visit and match these to later conversion events. This method provides nearly 100% match rates because Google can directly match the click ID to the conversion, rather than relying on potentially inaccurate customer details.

This process can be implemented manually, requiring significant technical effort, or automated using tools like Able CDP. Below, we outline both approaches to help you understand the steps involved and the benefits of automation.

Manual process for tracking offline conversions in Google Ads

To implement this solution manually, follow these steps:

1. Enable Auto-Tagging in Google Ads: Turn on auto-tagging in your Google Ads account to ensure the GCLID is appended to the URL when someone clicks on your ad.
2. Capture the GCLID: When a visitor lands on your website via a Google Ad, extract the GCLID from the URL parameter (e.g., ?gclid=...). This unique identifier is critical for tracking.
3. Store the GCLID: Save the GCLID in a cookie on the visitor's browser. Since the GCLID changes with each click and disappears on the next page load, update the cookie with the latest GCLID.
4. Include GCLID in Forms: Modify your forms (e.g., lead forms, enquiry forms) to include a hidden field that captures the GCLID from the cookie when the form is submitted.
5. Store GCLID in CRM: Ensure your CRM system stores the GCLID along with the lead or customer data for at least 90 days (the window for importing conversions back to Google Ads).
6. Prepare Conversion Data: When a conversion occurs (e.g., a purchase or booked meeting), create a CSV file containing:
   • GCLID
   • Conversion Name (must match the name in Google Ads)
   • Date of Conversion (e.g., YYYY-MM-DD HH:MM:SS)
   • Total Revenue (e.g., $1, static LTV, or actual revenue)
   • Currency (e.g., USD, GBP)
7. Upload to Google Ads: Upload the CSV file to Google Ads under Goals > Upload. You can do this manually or set up a schedule for automatic uploads by placing the file in a location (e.g., HTTPS or SFTP) that Google Ads can access regularly. Tools like Zapier can assist with automation.

A full technical overview is available in the Set Up Offline Conversion Tracking article at Google Ads help website.

This manual process requires technical setup, including website modifications to capture and store the GCLID, integration with your CRM to pass and store the GCLID, and potentially scripting or third-party tools for automating the upload process. Even if your CRM has built-in GCLID capture functionality, additional effort may be needed to manage uploads.

Automating the offline conversion upload to Google Ads with Able CDP

Able CDP Google Ads server-side tracking simplifies and automates the entire process of tracking offline conversions in Google Ads, eliminating manual intervention and reducing the risk of errors:

1. Able CDP's tracking code automatically captures click identifiers like GCLID when visitors arrive on your website.
2. Offline conversion data from CRM, payment systems etc. gets sent to Able CDP via APIs.
3. Able automatically matches conversions to click IDs.
4. Matched conversions uploaded to Google Ads API.

Able CDP streamlines this process, saving significant time and resources while providing more accurate data for campaign optimization.

→ See a step-by-step conversion tracking setup overview in our Getting Started guide.

Conclusion

If you run Google Ads campaigns but struggle with getting conversion tracking right, explore how Able CDP can solve your Google Ads conversion tracking. By automating the process of tracking offline conversions, Able CDP delivers higher match rates, better insights, and a more efficient workflow—allowing you to focus on scaling your campaigns effectively.