Largest Contentful Paint

What this check looks for

For pages with measured performance data, this check grades LCP — the render time of the largest visible element, usually a hero image or heading — against Google's published thresholds: at or under 2.5 seconds passes, between 2.5 and 4 seconds warns, and beyond 4 seconds fails. Pages without a measured LCP value report "na".

Why it matters

LCP measures how long a visitor waits before the main, meaningful content of the page actually appears — everything before that point is effectively dead time from the visitor's perspective, regardless of how fast the rest of the page loads afterward. It's one of Google's three Core Web Vitals and a confirmed ranking factor, so a slow LCP has a direct, measurable effect on search visibility, not just user experience. It also affects AI crawlers: a page that takes many seconds to render its main content risks timing out or being deprioritized by crawlers operating under their own fetch budgets, meaning the content may never get read at all.

How to fix it

Optimize whatever element is your LCP candidate — usually a hero image or a large block of text:

<!-- Preload the LCP image so it starts fetching immediately -->
<link rel="preload" as="image" href="/hero.webp" fetchpriority="high">
<img src="/hero.webp" alt="Acme wireless headphones" fetchpriority="high">

Also cut render-blocking CSS/JS ahead of the LCP element, compress and correctly size the image itself, and serve it from a CDN close to your visitors.