Core Web Vitals

Core Web Vitals are three metrics Google uses to describe the real-world experience of a page. Largest Contentful Paint (LCP) measures loading: good is 2.5 seconds or less. Interaction to Next Paint (INP) measures responsiveness: good is 200 milliseconds or less. Cumulative Layout Shift (CLS) measures visual stability: good is 0.1 or less. INP replaced First Input Delay (FID) as a Core Web Vital in March 2024.

Each metric is assessed at the 75th percentile of page loads, split by mobile and desktop. In other words, a page passes only if at least three out of four visits meet the good threshold. This field data comes from real Chrome users and is published in the Chrome UX Report, which tools like Google PageSpeed Insights and Search Console display. Pages with too little traffic may not have field data, in which case you rely on lab tests.

Core Web Vitals form part of the page experience signals Google considers in search, but they matter just as much for conversions. A slow, jumpy or unresponsive page frustrates people at the exact moment you want them to read your offer and click. Most fixes come down to sending less to the browser: smaller images, fewer scripts and fonts, faster hosting and reserved space for content that loads later.

How to improve it

• Check your page in Google PageSpeed Insights on mobile and look at field data if it is available.
• Compress and correctly size images, especially the main hero image.
• Remove or delay third-party scripts you do not need on the landing page.
• Set width and height on images and embeds so the layout does not jump.
• Use good hosting and caching to reduce server response time.

How PageScore checks it

PageScore runs a Google PageSpeed Insights mobile test and reports the performance score, LCP, CLS, total blocking time, server response time and total page weight. Total blocking time is a lab indicator related to INP; PageScore does not measure real-user INP from your analytics.