GM1X SEO Tools
Get expert help

Free Website speed & Core Web Vitals Tools

Real-user Core Web Vitals, PageSpeed and TTFB. 10 free tools, no sign-up.

Core Web Vitals Checker Check real-user Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift for any public URL, with lab metrics and fixes. Live check Page Speed Test Run a Lighthouse lab test on any public URL for mobile or desktop and get a performance score, key timing metrics, opportunities and diagnostics. Live check Website Speed Comparison Compare two public URLs side by side for real-user Core Web Vitals and Lighthouse lab metrics, such as your page against a competitor's. Live check TTFB Checker Measure Time to First Byte for a public URL three times, with DNS, TCP, TLS and server wait times shown separately for each run. Live check Page Size & Requests Checker See every request a public page makes, with type, size and timing, totals by resource type and a list of the heaviest files. Live check Render-Blocking Resources Checker Find the CSS and JavaScript files that block rendering and the unused code on a page, with estimated time and byte savings from Lighthouse. Live check Image Optimization Checker Find oversized, under-compressed, old-format and offscreen images on a public page, with estimated byte savings for each from Lighthouse. Live check GZIP/Brotli & Browser Cache Checker Check whether a page and its CSS, JavaScript and images are served with gzip or Brotli compression and long-lived Cache-Control or ETag headers. Live check Lazy Loading & Responsive Image Checker Audit every image in a page's HTML for lazy loading, fetchpriority, srcset and sizes, width and height attributes and modern formats. Live check Website Accessibility Checker Run the Lighthouse accessibility audit on a public URL and see failing checks for contrast, labels, alt text, ARIA, names and headings. Live check

About website speed & core web vitals tools

Speed affects how visitors experience your site, and Core Web Vitals (LCP, INP and CLS) are part of how Google assesses page experience. Start with the Core Web Vitals checker to see real-user field data from the Chrome UX Report, then use the page speed test and the focused checks for render-blocking resources, page weight, images, caching and lazy loading to find the causes.

Most tools here run Lighthouse through Google PageSpeed Insights or request the page from our server, so they work on public URLs only. Lab scores vary between runs; when field data and lab data disagree, field data reflects what real users experience.

Frequently asked questions

What are good Core Web Vitals scores?

Google rates a page as good when, at the 75th percentile of real users, Largest Contentful Paint is 2.5 seconds or less, Interaction to Next Paint is 200 milliseconds or less and Cumulative Layout Shift is 0.1 or less. INP replaced First Input Delay in March 2024. Field data comes from the Chrome UX Report over 28 days.

Why does my PageSpeed score change every time?

Lighthouse lab tests run on a simulated device and network, and results vary with server response, third-party scripts, network conditions and test location. Run a test a few times and look at the trend. For SEO decisions, rely more on the real-user Core Web Vitals field data than on a single lab score.

Can these tools test pages behind a login?

No. The speed tools fetch pages from our server or through Google PageSpeed Insights, so they can only test publicly reachable URLs. For staging or logged-in pages, run Lighthouse locally in Chrome DevTools instead. You can also deploy a temporary public preview URL and test that before going live.