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Google Call Conversion Tracking is a Google Ads feature that measures phone calls as conversions. It replaces the phone number on your website with a Google forwarding number through dynamic number insertion, then records details of the resulting calls and links them to the Google Ads click that brought the visitor. Because it relies on Google Ads cookies and sends call and click data to Google in the United States, it is an advertising tracker that requires consent.
Google Call Conversion Tracking is part of Google Ads. When a visitor arrives from a Google ad, a snippet on your site swaps your displayed phone number for a Google forwarding number, so that a call to that number can be attributed to the ad. Google records call details such as duration and caller area code and reports the call as a conversion in your Google Ads account, which lets advertisers measure phone driven leads.
The feature works with the Google Ads tag, which reads or sets cookies such as _gcl_aw and _gcl_au that store the Google click identifier, and _gac cookies used for conversion attribution. When a call is placed to the forwarding number, Google processes the caller phone number, call time, duration and the associated ad click. This links a real world phone call to an online advertising identifier.
The Google Ads cookies behind call conversion tracking are advertising cookies, so they are not strictly necessary and require prior consent under article 5(3) of the ePrivacy Directive, with consent as the legal basis under GDPR article 6(1)(a). The caller phone number is personal data, and linking it to an advertising click is profiling, so dynamic number insertion and the conversion tag must stay blocked until the visitor accepts advertising cookies.
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Google processes call and click data in the United States, so European personal data is transferred to a third country under the EU US Data Privacy Framework and standard contractual clauses, with Google Ireland typically acting as the EU controller. Because the feature combines a phone number with an advertising identifier, document the processing, the retention and the transfer, and inform callers that their call may be measured.
Gate the Google Ads tag and dynamic number insertion behind advertising consent, and use Google Consent Mode so that the tag respects the visitor choice. Confirm with developer tools that no _gcl cookie is set and the number is not swapped before consent, disclose Google Call Conversion Tracking and the United States transfer in your privacy policy, and set a conversion window and retention that match your purpose.
Websites using Google Call Conversion Tracking must obtain user consent under GDPR regulations.
DPIA considerations
Linking a caller phone number to a Google Ads click is profiling that involves personal data and a transfer to the United States, which can require a DPIA under GDPR art. 35, especially at scale. Assess the call data collected, the matching to advertising identifiers, the retention, Consent Mode and the transfer mechanism, and document the safeguards.
Sample consent text
With your consent, this website uses Google Call Conversion Tracking to measure phone calls that result from our Google ads. It replaces our phone number with a Google forwarding number and sets Google Ads cookies such as _gcl_aw, sending the call details and ad click to Google in the United States under standard contractual clauses. No Google Ads cookie is set and no number is swapped until you accept advertising cookies, and you can change or withdraw your consent at any time.
Third-party domains contacted
googleadservices.comwww.google.comgoogletagmanager.comCookies placed
| Name | Type | Duration | Purpose |
|---|---|---|---|
| _gcl_aw | First party, set by Google Ads | 90 days | Stores the Google Ads click identifier (GCLID) used to attribute a call conversion to an ad click. |
| _gcl_au | First party, set by Google | 90 days | Used by Google Ads and the conversion linker to store and read a click identifier for conversion attribution. |
| _gac_<property-id> | First party, persistent | 90 days | Stores Google Ads campaign information used to attribute conversions, including phone call conversions. |
Google Call Conversion Tracking places tracking cookies for advertising — comply with GDPR using FlowConsent.
It works with the Google Ads tag, which sets or reads advertising cookies such as _gcl_aw and _gcl_au, holding the Google click identifier, and _gac cookies used for conversion attribution. These are advertising cookies, not strictly necessary ones, and they link a call to an ad click.
Yes. The Google Ads cookies and the dynamic number insertion are advertising tracking, so they require prior consent under article 5(3) of the ePrivacy Directive. Keep the tag and the number swap blocked until the visitor accepts advertising cookies.
It relies on the visitor consent of GDPR article 6(1)(a) and ePrivacy article 5(3). The caller phone number is personal data and linking it to an advertising identifier is profiling, so legitimate interest is not an adequate basis.
Yes. Google processes the call and click data in the United States under the EU US Data Privacy Framework and standard contractual clauses, usually with Google Ireland as the EU controller. Disclose this transfer in your privacy policy.
Possibly, especially at scale. Linking phone numbers to advertising clicks is profiling with personal data and a US transfer, which can be high risk under GDPR article 35. Assess the call data, the matching, the retention and the transfer.
Block the Google Ads tag and dynamic number insertion until advertising consent, enable Google Consent Mode, verify no _gcl cookie or number swap occurs before consent, disclose the feature and the US transfer, and set an appropriate conversion window and retention.
You can measure calls with a privacy friendly call tracking provider hosted in the EU, or rely on consented first party analytics and manual lead tracking. Server side conversion import can also reduce the data shared at the browser, but the consent requirement remains.
List Google Call Conversion Tracking, the Google Ads cookies it uses, its purpose and the United States transfer in your cookie policy, and review it when you change your Google Ads conversion setup. Keep the consent categories aligned with how the calls are measured.