How do I improve my website's LCP value?
In short and in plain language
This is about how fast the main content of a page appears. Several steps play a part.
The server must answer fast. Files must not slow down the build of the page. The large image at the top must load quickly.
The server and blocking files are often where most is gained.
We make the server faster. We deliver the main image in modern formats. The browser then loads it first. So the main content often appears much faster.
LCP is the sum of four phases. First, the server response time (TTFB), reduced through optimized hosting, caching and, where appropriate, a CDN. Second, render-blocking resources such as non-critical CSS and synchronous JavaScript that delay the first paint. Third, the load time of the LCP resource itself, usually a large hero image. Fourth, the render time on the client, which can grow sharply in JavaScript-heavy frameworks without server-side rendering.
In practice the biggest lever almost always lies in the first two phases. We reduce TTFB through server optimization, deliver the LCP image in modern WebP or AVIF format and prioritize it via preload so the browser fetches it immediately. Once render-blocking scripts are deferred and critical CSS is inlined, LCP often drops considerably.