What is LCP?
TL;DR
LCP (Largest Contentful Paint) is a Core Web Vital that measures how long it takes for the largest visible content element on a page to fully render.
Last updated: 2026-03-09
Definition#
Largest Contentful Paint (LCP) measures the time it takes for the largest content element visible in the viewport to finish rendering. This element is typically a hero image, a large text block, or a video poster. LCP is one of the three Core Web Vitals.
Google considers an LCP of 2.5 seconds or less to be "good." Between 2.5 and 4 seconds "needs improvement." Over 4 seconds is "poor."
Common causes of slow LCP include unoptimized images, render-blocking CSS or JavaScript, slow server response times (TTFB), and client-side rendering that delays content display.
Why It Matters for AI Readiness#
LCP is one of the most important performance metrics for both user experience and crawler efficiency. AI crawlers allocate limited time per page. If your LCP is slow, the crawler may not wait for all content to load. The Speed & Performance factor weighs LCP heavily.
For optimization tips, see How to Improve Page Speed.
Related Concepts#
LCP is one of the three Core Web Vitals, alongside CLS and INP. It is preceded by FCP and affected by TTFB.
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