Core Web Vitals

Core Web Vitals are three metrics Google uses to quantify how a page feels to a real user. Largest Contentful Paint (LCP) measures loading — how fast the main content appears. Interaction to Next Paint (INP) measures responsiveness — how quickly the page reacts when you tap or click (it replaced First Input Delay in 2024). Cumulative Layout Shift (CLS) measures stability — how much the layout jumps around as it loads.

Optimise against field data (real Chrome users in the CrUX report and Search Console), not just lab scores in Lighthouse — a page can pass in the lab and fail for real people on mid-range phones. The usual culprits: an unoptimised or lazy-loaded hero image hurts LCP; heavy, blocking JavaScript hurts INP; images and embeds without reserved dimensions hurt CLS. Fix the worst-offending template first, because one bad template repeats across thousands of URLs.

Core Web Vitals are a lightweight ranking factor and a tie-breaker, not a magic lever — do not promise executives that passing them will move rankings on its own. Their real value is as a proxy for engagement and conversion, which is where the money is. Frame the work in revenue terms and bake performance budgets into the development process so the site does not silently regress after every feature launch.