WordPress Core Web Vitals Guide

Core Web Vitals turn broad “site speed” complaints into specific user-experience signals. Treat LCP, INP, and CLS as diagnostic categories rather than a single score to chase.

LCP

Investigate the largest above-the-fold content, server response, discovery priority, download time, and rendering.

INP

Investigate long main-thread tasks, JavaScript work, and slow event handling.

CLS

Investigate unstable dimensions, fonts, embeds, banners, and dynamically inserted content.

Use field and lab data together

Field data describes real-user experience where available; lab tests help reproduce and diagnose individual pages. Improve the underlying bottleneck, then retest.

Continue with LCP, INP, CLS, and PageSpeed Insights.

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