Performance

LCP Checker

Largest Contentful Paint measures how quickly the biggest visible element on the page loads. Google's target is under 2.5s. We'll also surface FCP and TTFB to help diagnose slow LCPs.

Uses Google PageSpeed Insights — typically 10–30 seconds. Results are lab data; real-user numbers may differ.

What is an LCP checker?

An LCP checker measures Largest Contentful Paint — how long the biggest visible element takes to render. This free LCP test runs Google PageSpeed Insights on any URL so you can check LCP and the metrics that cause it.

Diagnose & fix a slow LCP

Beyond the score, we surface FCP and TTFB so you can tell whether a slow largest contentful paint is server-side (high TTFB) or front-end (render-blocking resources, a heavy hero image). Optimize the hero image (WebP + preload), cut render-blocking CSS/JS, and reduce server time, then re-test.

What's a good LCP?

Aim for 2.5s or less on mobile. 2.5–4s needs improvement; over 4s is poor. LCP is a Core Web Vital, so improving it helps both users and rankings.

More Core Web Vitals tools

Check the rest: CLS Checker, INP Checker, TTFB Checker, and the full Page Speed Test.

Frequently asked questions

An LCP checker measures Largest Contentful Paint — how long the biggest visible element (hero image, heading or text block) takes to render. This free LCP test runs Google PageSpeed Insights on any URL and shows your LCP plus supporting metrics (FCP, TTFB) to help diagnose it.
Google considers LCP good at 2.5 seconds or less, needs-improvement up to 4s, and poor above 4s. Aim for under 2.5s on mobile, which is what most users and Google's ranking systems see.
Common fixes: optimize and preload the hero image (and serve WebP), reduce server response time (TTFB), remove render-blocking CSS/JS, and use a CDN. This checker surfaces FCP and TTFB so you can tell whether the delay is server-side or front-end.
Completely free and online, with no account required. It's part of WebsiteAuditTools' free suite of Core Web Vitals tools.