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What's actually putting your Core Web Vitals at risk?
Search Console or PageSpeed says LCP, INP or CLS is failing — but which part of the page is actually causing it? Paste your URL for an instant structural check: images missing size attributes, render-blocking scripts and stylesheets, an unmanaged font load, and slow server response time. Free, no signup.
Results
What this tool checks
Enter a URL and this tool fetches the site's public homepage — the same page a browser or search engine already loads — and looks for the structural, publicly-visible causes behind each of the three Core Web Vitals: images with no width or height attribute (the documented, primary cause of layout shift), render-blocking stylesheets and scripts sitting in the page's <head> with no defer or async (delaying first paint, and therefore LCP), a Google Fonts stylesheet loaded without a display strategy (invisible text, and sometimes a second shift when the real font swaps in), slow server response time (delays every paint metric equally, before a single byte of your page even arrives), and total script count as a rough proxy for the main-thread load behind a sluggish INP.
How to read the result
The verdict names a likely structural cause instead of handing you a raw score: at risk means a specific, fixable cause was found — either something in the markup (missing image dimensions, render-blocking assets) or a slow server response. Watch means nothing major, but a couple of things are worth keeping an eye on. Clean means no obvious structural risk was found on this page. None of these are your actual LCP, INP or CLS number — see below.
What this can't do
It deliberately doesn't try to reproduce your real Core Web Vitals score. That score is field data — gathered from real visitors, on real devices and real connections, over real time — and only a real browser (like the one behind PageSpeed Insights) or Google's own Chrome UX Report can measure it. This tool checks the static HTML for the structural causes that typically drive a poor score, in a couple of seconds, without rendering the page at all. It also only checks the homepage, and it can't see a self-hosted font's display setting if that lives in a linked stylesheet rather than the HTML itself.
If it comes back at risk
Missing image dimensions and render-blocking markup are exactly the kind of causes Search Console's Core Web Vitals report names without explaining how to fix — see Core Web Vitals explained for the full picture, or Core Web Vitals Fix if you'd rather have the specific failing metric diagnosed and fixed directly. If the report instead points at server response time, that's a hosting problem, covered by WordPress Speed Optimization.
FAQ
Questions about this checker
Is this the same as my real Core Web Vitals score in Search Console?
No. Search Console's Core Web Vitals report is built from real visitors on real devices and networks, gathered over weeks (field data). This tool can't see that data — it fetches your homepage's HTML once and checks it for the structural causes that typically drive a poor LCP, CLS or INP, as a fast first look rather than a replacement for field data.
Why does it check different things than PageSpeed Insights?
PageSpeed Insights runs a real Lighthouse audit inside an actual browser, which takes real rendering time. This tool checks the raw HTML for known structural causes — missing image dimensions, render-blocking scripts, an unmanaged font load — in a couple of seconds, without needing to render the page at all.
What if it says “clean” but Search Console still shows a failing metric?
That can happen. Search Console's field data reflects real visitors on real connections and devices, including slow ones this tool never simulates. A clean structural result rules out the most common markup-level causes; it doesn't rule out everything a real visitor might experience.
It found missing image dimensions — what should I do?
Add explicit width and height attributes (or a CSS aspect-ratio) to the affected images so the browser can reserve their space before they load. See Core Web Vitals Fix if you'd rather have the specific failing metric diagnosed and fixed directly.
Does it check every page on my site?
No — like the other free tools here, it checks the public homepage only. A slow product page or a heavy blog template can carry entirely different issues a homepage-only scan won't see.
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