Core Web Vitals are three metrics Google uses to measure real user experience on a page, collected from actual Chrome users and used as a ranking input. LCP (Largest Contentful Paint) measures how fast the main content appears (target under 2.5 seconds). INP (Interaction to Next Paint) measures how quickly the page responds to taps and clicks (target under 200 milliseconds). CLS (Cumulative Layout Shift) measures whether the layout jumps around while loading (target under 0.1).
A page ‘passes’ when it hits all three targets for at least 75% of real visits. Only around 49% of WordPress sites pass on mobile, which is both the industry’s embarrassment and an opportunity: passing scores are a genuine competitive edge in rankings and conversions at once.
For WordPress specifically, the usual failure causes are heavy themes and builders (INP), unoptimized images and slow hosting (LCP), and late-loading fonts, banners, or images without dimensions (CLS). Each has a known fix path; the scores respond to engineering, not luck.
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