Google Core Web Vitals

There are three Core Web Vitals Google encourages all website owners implement to enhance the user experience.

Loading LCP (Largest Contentful Paint)

The time it takes for a page’s main content to load. An ideal LCP measurement is 2.5 seconds or faster.

LCP can be improved through optimizing your website’s server, caching static HTML on your server, and optimizing/minimizing your CSS and JavaScript.

Interactivity FID (First Input Delay)

The time it takes for the page to respond to clicks, scrolls, or keyboard input. An ideal measurement is less than 100 ms.

Poor FID is caused by heavy JavaScript execution. Optimizing how JavaScript parses, compiles, and executes on your web page will directly reduce FID.

Visual Stability CLS (Cumulative Layout Shift)

The shifting of text, links, pictures, ads, or other visual elements during the site’s loading process. For good user experience, CLS should be less than 0.1.

A bad CLS score is usually the result of poor planning for how space on a website will be used, especially for items that take extra time to load. The browser should know how much space needs to be reserved for images, ads, and dynamically injected content. Images should be assigned an aspect ratio or static dimensions should be defined.