TOOL GUIDE
Website speed test
A website speed test with separate lab diagnostics and available real-user measurements. Inspect the test conditions and prepare a clear developer checklist.
Read the walkthroughHow does a website speed test measure page performance?
Enter a page URL to inspect its loading performance. The report separates a controlled lab test from available real-user data and identifies the conditions behind each result. If field data is unavailable, the tool will say so instead of substitute a lab score for a real-user assessment.
A PRACTICAL WALKTHROUGH
When to use it and what to prepare
For business owners and developers investigating slow landing pages, especially when mobile visitors struggle to load the main content.
- Use the exact landing-page URL, rather than only the domain.
- Choose mobile or desktop and note whether a recent release changed images, scripts or fonts.
Work through these steps
- Select a device and request the page test when the live connection is available.
- Read the lab measurement and real-user section separately.
- Use the evidence to form a small performance task list, then compare like-for-like tests.
ILLUSTRATIVE EXAMPLE
Put the method into context
Illustrative example: a lab run reports a slow Largest Contentful Paint (LCP) measurement while URL-level field data is unavailable. Use a separate full Lighthouse investigation to identify the responsible element; do not describe missing field data as a Core Web Vitals pass.
How to interpret the result
Lab tests show one controlled run. Field data reflects the users and period represented by the source. An origin-level result describes more than the exact URL and should stay labeled that way.
Get a more useful result
- Repeat comparable tests before attributing a change to one edit.
- Keep mobile and desktop results separate when preparing a developer brief.
Keep these limits in mind
- Network conditions and page changes can alter individual lab runs.
- The test does not replace a complete accessibility or usability review.
The method and its scope
One mobile or desktop Lighthouse request, plus separate CrUX URL data with a labeled origin fallback. TBT is never presented as INP.
Choose your next step
Read the supporting SEO guideReview the service scopeQuestions about website speed test
Can I use this tool now?
The usage guide is available. The interactive function still awaits setup and checks; this informational page does not run scans or collect tool inputs.
Why can a speed test disagree with real-user data?
A lab test uses controlled conditions for one run. Field data describes actual visits over a reporting period, so the two measure different situations.
Does missing CrUX data mean my page is fast?
No. Missing field data means that measurement is unavailable. Use the lab evidence for diagnosis without treating it as a real-user pass.
What is the scope of website speed test?
One mobile or desktop Lighthouse request, plus separate CrUX URL data with a labeled origin fallback. TBT is never presented as INP.