How This Website Speed Test Works
Enter a URL and this website speed test runs a real, live Lighthouse audit through Google's own PageSpeed Insights infrastructure, the same lighthouse test online that powers Google's own tooling, not a simulated or estimated score computed on our own servers. Unlike a lightweight website speed checker that only measures raw load time, this returns the full report pagespeed insights itself produces: an overall performance score, four category scores (Performance, Accessibility, Best Practices, SEO), every metric, and the exact ranked list of what to fix, moments after the real audit completes.
Field Data vs Lab Data: Understanding Core Web Vitals
A core web vitals test reports two genuinely different kinds of data, and this tool shows both side by side instead of picking one. Lab data comes from Lighthouse running a single synthetic test against your page right now, useful for reproducible before/after comparisons. Field data, when available, comes from the Chrome UX Report, aggregated real measurements from actual Chrome users who visited your site over the past 28 days, the same data Google's own ranking systems use. This core web vitals checker surfaces LCP, CLS, and INP from both sources, plus FCP and TTFB from field data, so you can see not just how your page performed in one lab run, but how real visitors actually experienced it.
Reading Opportunities and Diagnostics
Every issue that has a quantifiable fix appears as an opportunity, sorted by estimated savings so the biggest wins surface first, while structural issues that don't have a single numeric savings value (like missing alt text or an already-small unminified asset) appear as diagnostics instead. This website performance test doesn't stop at a bare score: each opportunity and diagnostic includes Lighthouse's own explanation of why it matters and, where relevant, a table of the specific offending resources, so fixing a problem doesn't require guessing which image or script it's actually about.
Common Uses and Limitations
This site speed test is commonly run before a launch, after a redesign, or when investigating a sudden traffic or ranking drop, since Core Web Vitals are a confirmed Google ranking signal. One honest limitation worth knowing: a mobile page speed test result can vary somewhat between runs even for the exact same page, since Lighthouse's lab throttling introduces normal real-world variance, run it a couple of times if a score looks like an outlier. Field data also isn't available for every URL, Google's Chrome UX Report only reports on origins and pages with enough real Chrome traffic to be statistically meaningful, a low-traffic page may show lab data only.