Largest Contentful Paint
Also called LCP
A Core Web Vital that measures when the largest image or text block in the viewport appears. Good is 2.5 seconds or less.
Largest Contentful Paint, or LCP, measures how long it takes for the largest visible image or block of text in the viewport to appear, counted from when the page starts loading. It is Google's main Core Web Vital for loading speed because it approximates the moment the visitor sees the main content. Good is 2.5 seconds or less, needs improvement is up to 4 seconds and poor is above 4 seconds, assessed at the 75th percentile of page loads.
On most landing pages the LCP element is the hero image, a background image or the main headline. LCP can be broken into four parts: the time for the server to respond, the delay before the browser starts loading the LCP resource, the time to download it, and the delay before it is drawn. Slow hosting, large images, images loaded late by scripts or lazy loading, render-blocking CSS and JavaScript and web fonts that hide text can all push it up.
For conversions, LCP matters because it is roughly when visitors see your headline and offer. Until then they are looking at an empty or half-loaded screen, and on mobile networks some of them leave before anything useful appears.
How to improve it
- Compress the hero image, serve it in a modern format like WebP or AVIF and size it for mobile screens.
- Do not lazy-load the hero image; load it early, and consider a fetchpriority=high hint on it.
- Reduce server response time with better hosting, page caching and a CDN.
- Remove or defer render-blocking scripts and unused CSS.
- Make sure text shows immediately while web fonts load.
How PageScore checks it
PageScore reports LCP from a Google PageSpeed Insights mobile test, along with server response time and total page weight, which are common causes of a slow LCP.