Core Web Vitals Checker: Do You Pass Google's Thresholds?

A Core Web Vitals checker takes the LCP, INP and CLS numbers you already have from PageSpeed Insights or Search Console and tells you instantly which ones pass Google's published thresholds, without needing to interpret three separate scales yourself.

The three metrics explained

Largest Contentful Paint measures loading speed, tracking how long the biggest visible element takes to render. Interaction to Next Paint measures responsiveness, tracking the delay between a user action and the page's next visual update. Cumulative Layout Shift measures visual stability, tracking how much content jumps around unexpectedly while the page loads. Google needs all three in the good range for a page to count as passing.

Why the thresholds matter

Google sets a good, needs-improvement and poor band for each metric based on research into what users actually perceive as fast or slow. A page can look fine to you on a quick desktop connection while still failing INP for the many visitors on slower phones and networks, which is why field data from real users matters more than a single lab test.

Fixing common issues

Slow LCP is usually a large hero image, render-blocking CSS or JavaScript, or a slow server response. Poor INP is often heavy JavaScript that blocks the main thread during interactions, especially on pages with a lot of client-side rendering. Layout shift is most often caused by images or ads without a reserved size, or fonts that swap in late and push content down. Fixing the biggest offender first usually moves the overall verdict from poor to needs improvement or good, which supports the kind of technical foundation behind solid technical SEO.