What Is Largest Contentful Paint (LCP) and How to Fix It
LCP measures when the most important visible content on a page has loaded. It is the Core Web Vital most directly tied to perceived speed — and the one most businesses fail. Here is what moves the score and how to fix it.
What is lcp seo? LCP stands for Largest Contentful Paint. It is a Core Web Vital. It measures when the largest visible element on a page finishes loading. That element is usually a hero image, a large heading, or a video poster frame. The metric matters for one reason. It is the closest proxy for when a user feels the page is "ready." Say a page renders text fast but loads a slow hero image. It will still score a poor LCP. The fast text does not save it.
Google sets a clear bar for a good LCP score. It must be under 2.5 seconds. This is measured at the 75th percentile of real user loads. Pages above 4 seconds are rated poor. These pages face a ranking disadvantage in search results. For more context on Core Web Vitals, see what-is-cls and what-is-inp.
LCP issues get found and fixed in all web builds and audits. The causes are always the same. The fixes are simple and easy to do.
What Causes Poor LCP Scores
Slow Server Response Time (TTFB)
Time to First Byte (TTFB) sets how fast the browser can start rendering. A slow hosting server can hurt it. Unoptimized database queries on a dynamic site can too. So can a CMS without server-side caching. These issues can add 500ms to 2 seconds before the browser gets the HTML. On CDN-delivered static sites, TTFB is usually under 100ms. That's why static site generators have an LCP advantage over server-rendered dynamic CMSes.
Render-Blocking Resources
Some stylesheets load in the <head>. They block rendering. Some scripts do too. This delays LCP. The browser can't paint anything yet. It must fetch those resources first. Then it must parse them. Three fixes help most. Defer non-critical JavaScript. Inline critical CSS. Remove or delay third-party scripts. These are the main levers. They cut render-blocking time.
Unoptimized LCP Image
Say the LCP element is an image. Its file size and format decide how long it takes to load. A 2MB JPEG hero image is a common mistake. A 150KB WebP often gives the same quality at a fraction of the size. This is one of the most common causes of poor LCP on business sites. Serve images in WebP or AVIF format. Size them to the actual display dimensions. Do not ship oversized images that CSS scales down. Deliver them from a CDN edge node close to the user.
Missing fetchpriority or Preload Directives
Browsers don't always load key elements first. Two fixes help: - Add `fetchpriority="high"` to the main image. - Add `<link rel="preload">` in the head section. Both tell browsers to start loading earlier. On slow sites, this can speed things up by 500ms to 1.5 seconds.
How to Diagnose Your LCP Element
Open Chrome DevTools. Go to the Performance tab. Record a page load. Look for the "LCP" marker in the timeline. The details panel shows the matching element. PageSpeed Insights (pagespeed.web.dev) and the Chrome User Experience Report (CrUX) give field data. Field data means actual LCP scores from real users, not lab simulations. Google uses that field data in its ranking system.
LCP is the metric that best answers one question from the user's view: how fast does this feel? Most LCP failures are image optimization problems, not infrastructure problems. That means you can fix them without a platform migration.
The Fix Priority Order
Identify the actual LCP element via DevTools or PageSpeed Insights before making any changes
Change the LCP image to WebP or AVIF. Size it to fit the screen. This often makes LCP better by 30-60%. It works best on picture-heavy sites.
The LCP image needs priority. Add `fetchpriority="high"` to it. Also add `<link rel="preload">` in the `<head>`. Make sure they match.
Deliver the LCP image from a CDN edge node with aggressive cache headers
Check render-blocking scripts. Defer them if they aren't critical. Do this after the first paint.
Get a Core Web Vitals audit for your site
Book a free Brand and Growth Assessment. See exactly how Through The Glass Creatives would approach it.
Sources
- Google, "Optimize Largest Contentful Paint" (2025)
- Web.dev, "LCP: What It Is and How to Improve It" (2025)
- HTTP Archive, "State of the Web: Core Web Vitals Report" (2025)
- Cloudflare, "Image Optimization and LCP Impact Study" (2024)
