Technical SEO
Largest Contentful Paint (LCP)
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What is Largest Contentful Paint (LCP)?
Largest Contentful Paint (LCP) measures the time from when a page starts loading to when the largest visible content element — typically a hero image, video thumbnail, or large text block — is rendered in the viewport. It is the primary Core Web Vital for measuring perceived load speed. Google considers an LCP of 2.5 seconds or faster to be "Good," 2.5–4 seconds "Needs Improvement," and above 4 seconds "Poor."
Common causes of poor LCP include slow server response times (TTFB), render-blocking JavaScript or CSS, slow resource load times (especially large images), and client-side rendering delays. Optimizing LCP typically involves compressing and serving images in next-gen formats (WebP/AVIF), preloading key resources, improving server response times, and deferring non-critical JavaScript.
Why it matters for SEO
LCP is the Core Web Vital most directly correlated with how fast a page feels to users, making it the highest-priority performance metric to optimize. A slow LCP signals to both users and Google that the page delivers a poor loading experience, which can suppress rankings and increase abandonment.
Example
On an online furniture store, the largest element on product pages is the main product photo, and it appears after about five seconds on mobile because it is lazy-loaded and served at full resolution. Removing lazy-loading from that one image, adding fetchpriority="high", and serving a correctly sized WebP brings LCP down toward Google's 2.5-second "good" threshold.
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