Loading performance affects how people use a website, but there is no universal delay that produces a fixed conversion loss on every site. Measure the actual pages and customer journeys before turning an industry benchmark into a revenue claim.
Use relevant performance measures
Review loading, responsiveness, and visual stability with the current Core Web Vitals definitions. Distinguish field data from diagnostic laboratory tests. A desktop score on one page does not establish the experience for all mobile users, networks, and pages.
Inspect the causes
Review media sizes, script and stylesheet work, third-party services, caching, rendering, and server responses. Prioritize problems that affect important tasks, such as reading service details or submitting an inquiry. A higher test score is useful only in the context of a functioning experience.