The The 75th percentile is the threshold at which at least 75 % of page views reach the good value. Core Web Vitals are assessed at this point, not at the average.Open glossary entry → is a statistical threshold: it describes the value that at least 75 % of page views reach or stay below. The Core Web Vitals are a set of Google metrics that measure real-world user experience in the areas of loading performance, interactivity and visual stability.Open glossary entry → are deliberately assessed at this point rather than via a simple average, because averages can be misleading.
In concrete terms, a page is considered good for a metric if at least 75 % of page views meet the good threshold, for example a Largest Contentful Paint (LCP) measures when the largest visible content element in the viewport has loaded, representing the perceived loading speed.Open glossary entry → of no more than 2.5 seconds. Why this matters:
- a page may seem fine for fast desktop users,
- mobile users with a weak connection may still have poor values,
- individual very slow outliers do not decide on their own, but the majority must have a good experience.
For this reason, mobile and desktop should be analysed separately. The 75th percentile ensures that not only the fastest users count, but that the broad majority has a good experience.