I'm building my first website and have read that keeping Largest Contentful Paint (LCP) low can help with search visibility and user experience. I've been testing the site with PageSpeed Insights, but the results vary dramatically—from around 2.5 seconds in one test to 22 seconds in another. Is that normal variation in the testing environment, or does it point to a problem with my website or hosting? The page also has an introductory animation where a list of words appears one at a time. Could that animation be delaying or making the LCP measurement unreliable?
4 Answers
The first thing to do is check the LCP element identified in the PageSpeed diagnostics or Chrome DevTools Performance panel. If it’s part of the word animation, that’s probably the main cause. Elements that start hidden with `opacity: 0`, or that are inserted and changed by JavaScript, may not count as the LCP until the animation finishes. On a throttled mobile test, a short animation can take much longer than expected.
The animation is likely contributing, but unstable backend response time can make the swings even worse. Slow time to first byte, delayed font downloads, script execution, and a throttled CPU can all postpone when the animated content appears. Check your server timing as well as the animation, and make sure the primary content can render without waiting for JavaScript.
The safest fix is to make the main headline or other likely LCP content visible immediately in the initial HTML. Keep the word-by-word effect for secondary or decorative content, or avoid hiding the primary text behind a long opacity animation. The goal isn’t to remove every animation—it’s to avoid delaying the main above-the-fold content that users need to see first.
There are two factors here. PageSpeed’s lab test simulates a slower phone and network, so each run can vary—especially if your server has inconsistent response times or cold starts. Run it several times and pay more attention to the median than one unusually high result. Also check the real-user field data when it’s available, since that reflects actual Chrome visits and is more useful than a single synthetic run.
A new site may not have enough real-user traffic for field data yet, so in that case you’ll need to use repeated lab tests while debugging.