Full Answer

The headline number, roughly 15-30% more conversions recovered, describes the gap between what actually happened and what client-side tracking managed to capture. It's worth being precise about what that means: server-side tracking doesn't generate new revenue, it stops under-counting the revenue you already earned. Those conversions were real; the browser just never reported them.

The size of the gain depends on your audience. A store with heavy Safari and mobile traffic, or a privacy-conscious customer base running ad blockers, loses more to client-side tracking and therefore recovers more when measurement moves server-side. A store whose visitors mostly use unhardened Chrome will see a smaller delta. The 15-30% range is a typical middle, not a guarantee, which is the honest way to read any such figure.

Accuracy improves in a second way that the percentage doesn't capture: reliability. A client-side tag only records an event if the script loads and runs, and anything from an ad blocker to a slow network to a privacy setting can stop that. A server-side event fires from infrastructure you control, so it isn't subject to the same failure modes. For a WooCommerce store, the combination, more conversions captured and each one captured more dependably, is why server-side measurement is treated as the accuracy baseline rather than an optional upgrade.