Under Universal Analytics, bounce rate was computed as single-pageview sessions with no further interaction event, divided by total sessions in the window. GA4 deprecated standalone bounce rate in favor of engagement rate: a session counts as engaged if it lasts at least 10 seconds (the default threshold, adjustable in the property’s data-stream settings), fires at least one key event (the GA4 rename of “conversion event”), or includes two or more pageviews. Bounce rate in GA4 reports is therefore 1 − engagement rate — the same idea, inverted, with a defined floor on what “engaged” means.
The number is a weak standalone quality signal for a DTC storefront. A single-page session can mean the visitor bounced off bad creative, the wrong audience, or a slow page — or it can mean intent was satisfied on arrival (spec lookup, store-locator visit, blog read). The metric alone does not separate the two, which is why operators reach for it less often than add-to-cart rate or conversion rate when reading storefront health.
Bounce rate is most readable where a single-page exit is closer to a defection than a satisfied lookup: paid-traffic landing pages, PDPs in an acquisition funnel, anywhere the next action is well-defined. It is noisiest on content surfaces where one-page visits are the design — blog, glossary, support, FAQ. Read it alongside add-to-cart rate and conversion rate at the same session denominator; it is an upstream signal, not a standalone KPI.