Core Web Vitals

The three metrics

Largest Contentful Paint (LCP) is how long the main content takes to appear; good is 2.5 seconds or less. Interaction to Next Paint (INP) is how quickly the page responds to clicks and taps; good is 200 milliseconds or less. Cumulative Layout Shift (CLS) is how much the layout jumps while loading; good is 0.1 or less.

Field data and lab data

Google uses field data: measurements from real Chrome users over the past 28 days. Lab tools such as Lighthouse simulate a load and are useful for finding causes, but their numbers can differ from what real visitors experience.

How much they matter

Page experience is a ranking signal, but relevance matters far more: a fast page that does not answer the query will not outrank a slower one that does. Good vitals matter most for visitors, who leave slow and jumpy pages, especially on launch day when traffic arrives on phones.

Common fixes

For slow LCP: serve images at the right size and in modern formats, preload the main image, and reduce server response time. For poor INP: break up long JavaScript tasks and defer scripts that are not needed straight away. For layout shift: give images and embeds fixed dimensions and reserve space for anything that loads late, such as banners.

Example

A landing page's hero image loads late, giving an LCP of 4.1 seconds; preloading the image and serving it at the right size brings it under 2.5 seconds.

Questions people ask

Do Core Web Vitals affect rankings?

They are part of Google's page experience signals, but relevance and content quality matter much more. Fix poor vitals for visitors first.

Where can I see my Core Web Vitals?

In Google Search Console's Core Web Vitals report and in PageSpeed Insights, which shows field data from real Chrome users when enough is available.