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Page speed checker

Lighthouse scores, Core Web Vitals and the top fixes for any page.

How to use it

  1. Paste a page URL. Test the pages that matter most: your homepage, pricing and top landing pages.
  2. Pick mobile or desktop. Google ranks on mobile, so start there.
  3. Run the test. Google runs Lighthouse on the page. It takes 10 to 60 seconds.
  4. Fix the top items. Start with the opportunities that save the most time.

Lab data and field data

This checker runs Google PageSpeed Insights, which gives you two different things:

  • Lab data comes from a single Lighthouse run on a simulated mid-range phone over a throttled connection. It is repeatable and good for debugging, but it is one synthetic visit.
  • Field data comes from the Chrome UX Report: real Chrome users visiting the page over the last 28 days, reported at the 75th percentile. This is what Google uses for the page experience signal. Smaller sites often have none yet.

The Core Web Vitals

  • Largest Contentful Paint (LCP) is how long the main content takes to appear. Good is 2.5 seconds or less.
  • Interaction to Next Paint (INP) is how quickly the page responds to taps and clicks. Good is 200 ms or less. It needs real users, so lab runs report Total Blocking Time (TBT) as a stand-in.
  • Cumulative Layout Shift (CLS) is how much the page jumps around while loading. Good is 0.1 or less.

Fixes that usually matter most

  1. Serve images at the right size and format. WebP or AVIF, with width and height set so the layout does not shift.
  2. Cut JavaScript. Unused scripts and heavy third-party tags are the main cause of slow interactions.
  3. Load the hero image early. Do not lazy-load the LCP image; preload it if it is set in CSS.
  4. Cache and compress. Check Cache-Control and Brotli with the HTTP header checker.

Speed is a tie-breaker in rankings rather than a trump card, but it has a direct effect on bounce and conversion. Lab scores move a few points between runs, so compare trends, not single numbers.

What you get

  • Performance, SEO, accessibility and best-practices scores
  • LCP, CLS, INP, FCP, TBT and Speed Index
  • Real-user Chrome UX Report data when available
  • Top five fixes by time saved
  • Mobile and desktop

Questions

What is a good PageSpeed score?

90 to 100 is good, 50 to 89 needs improvement, under 50 is poor. Mobile scores are usually much lower than desktop because Lighthouse simulates a mid-range phone on a slow connection.

Why does my score change every time I test?

Lighthouse runs are affected by server response time, network conditions and third-party scripts, so scores vary by a few points. Run it two or three times and look at the trend.

What is the difference between lab and field data?

Lab data is one simulated visit, useful for debugging. Field data is real Chrome users over 28 days, and it is what Google uses for ranking. A page can score well in the lab and still fail in the field, or the reverse.

Why is there no field data for my page?

The Chrome UX Report only includes pages and sites with enough real Chrome traffic. New or small sites often have none. The lab numbers are still useful in the meantime.

Do Core Web Vitals affect rankings?

Yes, as part of Google's page experience signals, but relevance and content quality matter far more. Treat speed as a tie-breaker and a conversion win.