Tools
Free page speed checker
Enter your URL and we'll check your Core Web Vitals against Google's actual ranking thresholds, with real visitor data when available, lab estimates when not. Mobile and desktop, side by side.
Google uses three Core Web Vitals as ranking signals: Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS). Not the Lighthouse performance score, the actual metrics measured on real visitors' devices.
Most speed-testing tools give you a score out of 100 and leave you to figure out what it means for rankings. This tool tells you directly: is speed a ranking problem for this URL, or not?
Chrome User Experience Report (CrUX) data is collected from real Chrome users who visit your site. If Google has enough traffic data for your URL, we show field metrics, the actual experience visitors are having. This is what Google uses as a ranking signal. Not lab tests. Not simulations. Real visits on real devices on real networks.
Lab data comes from Lighthouse running in a controlled environment. It's useful for diagnosing specific issues, but it's a simulation, it doesn't reflect what real visitors experience. If we don't have CrUX data for your URL, we show lab estimates and say so clearly. The distinction matters because lab scores are often worse than real-world performance, and sometimes better. Neither is wrong, they're measuring different things.
What we check
The metrics that actually affect rankings
Google evaluates four metrics, three Core Web Vitals that directly affect rankings, plus a server response time that underpins them all. Here's what each one measures and where the thresholds sit.
- 01LCP (Largest Contentful Paint)
How long until the largest visible element, usually the hero image or main heading, finishes loading. Google's threshold: under 2.5 seconds is good, over 4 seconds is poor. LCP is the metric most directly affected by image pipeline decisions image size, format, and priority loading.
- 02INP (Interaction to Next Paint)
How quickly the page responds when someone clicks, taps, or types. Google's threshold: under 200 milliseconds is good, over 500 milliseconds is poor. INP replaced FID (First Input Delay) in March 2024 and is a harder test, it measures every interaction, not just the first one.
- 03CLS (Cumulative Layout Shift)
How much the page layout shifts while loading. Google's threshold: under 0.1 is good, over 0.25 is poor. CLS happens when images load without reserved space, fonts swap, or ads inject content that pushes elements around. It's the metric that makes users feel like the page is unstable.
- 04TTFB (Time to First Byte)
How quickly the server responds to the initial request. TTFB isn't a Core Web Vital, but it's a foundation metric, a slow server makes everything else slower. It reflects hosting quality, caching strategy, and server-side processing time.
The tool gives you one of three verdicts based on your Core Web Vitals:
- Not a problem Your Core Web Vitals pass Google's thresholds. Speed is not hurting your rankings for this URL. There may still be room to improve the user experience, but from a ranking-signal perspective, you're clear.
- Needs work One or more metrics are in the warning zone. Google isn't penalising you yet, but you're close to the threshold. This is the zone where a slow day, a traffic spike, or a large image upload could push you into poor territory.
- Hurting rankings One or more Core Web Vitals fail Google's thresholds. Speed is actively working against your search rankings for this URL. The tool tells you which metric is failing and what the threshold is, so you know exactly what needs fixing.
The Lighthouse performance score is the number most people fixate on. It's a weighted composite of several lab metrics, scored out of 100. A score of 90+ feels good. A score of 40 feels bad.
But Google doesn't use the Lighthouse score as a ranking signal. It uses the three Core Web Vitals, LCP, INP, and CLS, measured on real visitors via the Chrome User Experience Report. A site can score 55 on Lighthouse and pass all three CWV thresholds. A site can score 95 on Lighthouse and fail CLS because of a layout shift the lab test didn't catch.
We show the Lighthouse score because it's useful context and people expect it. But the verdict, the part that tells you whether speed is actually affecting your rankings, is based on the Core Web Vitals thresholds, not the score.
We run both mobile and desktop checks because the results are often very different. A page that passes on desktop can fail on mobile, slower processors, smaller screens, and mobile network conditions all affect the metrics.
Google uses mobile-first indexing, which means the mobile version of your page is what Google evaluates for rankings. If your mobile Core Web Vitals fail but desktop passes, you have a ranking problem, even if most of your visitors are on desktop.
You can tab between mobile and desktop results without triggering a new test. Both run in parallel when you enter your URL, and the results are cached for the session.
This is a single-URL check powered by Google PageSpeed Insights. It doesn't crawl your entire site, and it doesn't check technical SEO basics like metadata, structured data, or crawlability, use our site scanner for that.
It also doesn't diagnose the root cause of performance issues. If your LCP is slow, the tool tells you it's slow and what the threshold is. Figuring out whether the cause is image size, server response time, render-blocking JavaScript, or font loading requires a deeper investigation, either manual analysis of the Lighthouse diagnostics or a proper performance audit.
What this tool does well is answer the question most businesses actually need answered first: is speed hurting my rankings, or not?
FAQs
Frequently asked questions
Yes. No signup, no email required. Paste a URL and get your results immediately.
Field data comes from real Chrome users visiting your site (collected via the Chrome User Experience Report). Lab data comes from Lighthouse running a simulated page load in a controlled environment. Field data is what Google uses for ranking signals. Lab data is useful for diagnosing specific issues but doesn't reflect real visitor experience.
Mobile tests simulate a mid-tier phone on a slower network. Real mobile devices have less processing power and often worse network conditions than desktop. Since Google uses mobile-first indexing, the mobile result is what matters for rankings.
For ranking purposes, yes. The Lighthouse score is a lab-based composite that includes metrics Google doesn't use as ranking signals. If your three Core Web Vitals (LCP, INP, CLS) pass on real visitor data, speed isn't hurting your rankings.
Google needs enough Chrome user traffic to your specific URL to generate field data. Newer pages, lower-traffic sites, or recently changed URLs may not have enough visits yet. Lab estimates are still useful, they're just not what Google uses for ranking decisions.
Whichever Core Web Vital is failing. LCP is most commonly caused by unoptimised images, wrong size, wrong format, no priority loading. CLS is usually caused by images without reserved space or late-loading content that shifts the layout. INP is typically caused by heavy JavaScript blocking the main thread during interactions.
After any significant change to your site, new images, code deployments, hosting changes, or third-party script additions. Core Web Vitals can shift with content updates, so checking after a round of new content is worth doing. CrUX field data updates on a rolling 28-day window, so changes take a few weeks to show in real visitor metrics.