Definition
LCP (Largest Contentful Paint) measures the time needed to display the largest visible content element in the viewport. This element can be a hero image, a video, a dominant text block, or an SVG element. Google recommends an LCP under 2.5 seconds for a good user experience and considers it a ranking signal via Core Web Vitals. A slow LCP is often caused by unoptimized images (format, size, compression), high server response time (TTFB), CSS or JavaScript resources blocking rendering, or misconfigured lazy loading on the main image. To optimize LCP, it is recommended to preload the LCP image via a link preload tag, use modern formats (WebP, AVIF), and serve images from a CDN.
Key Points
- Google recommended threshold: under 2.5 seconds
- Applies to the largest visible element (image, video, text block)
- Optimizable via image compression, preload, and TTFB improvement
Practical Examples
Unoptimized hero image
A 3 MB PNG hero image causes an LCP of 6 seconds. After conversion to WebP and resizing, LCP drops to 1.8 seconds.
Preloading critical resources
Adding preload on the font and main image reduces LCP from 4.2s to 2.1s on a business website.
Frequently Asked Questions
A good LCP score is under 2.5 seconds. Between 2.5s and 4s, it needs improvement. Above 4 seconds, Google considers it poor.
Optimize images (modern formats, compression), use preload for critical resources, improve server TTFB, and minimize render-blocking CSS/JS.
Go Further with LemmiLink
Discover how LemmiLink can help you put these SEO concepts into practice.
Last updated: 2026-02-07