Full Answer

The discrepancy traces to where each platform collects its data. Google Ads records a click the moment someone taps an ad, then attributes any conversion within its lookback window — typically 30 days — back to that click. The counting happens on Google’s servers, so ad blockers never touch it.

GA4 works differently. It fires a JavaScript tag in the visitor’s browser, and that tag must load, execute, and send data to Google’s collection endpoint. If an ad blocker prevents the script from loading, or if Safari’s Intelligent Tracking Prevention (ITP) deletes the _ga cookie before the visitor returns, GA4 never sees the event. Orbit Media’s research confirms that analytics tools routinely undercount traffic because client-side scripts are the first casualty of privacy tooling (Orbit Media, 2024).

The fix is architectural: move event capture from the browser to a first-party server endpoint. When a purchase fires server-side, it reaches GA4 and Google Ads through a path no browser extension can block. The two platforms still attribute differently — Google Ads credits the click, GA4 credits the session — but the raw event count converges. For a deeper look at how ad blockers hide WooCommerce data, see [How much conversion data do ad blockers hide from WooCommerce stores?](https://seresa.io/seed/data-loss-recovery/how-much-conversion-data-do-ad-blockers-hide-from-woocommerce).