How to test your website speed
- Paste the full URL of the page you want to test. Test your home page and your most important landing pages separately.
- Choose mobile or desktop. Start with mobile: Google indexes the mobile version of your site, and mobile scores are usually lower.
- Click “Test speed”. The test loads the page in a real browser and takes 20 to 60 seconds.
- Work through the fixes from the top; they are sorted by the time they could save.
Core Web Vitals explained
| Metric | Measures | Good | Poor |
|---|---|---|---|
| Largest Contentful Paint (LCP) | When the main content appears | ≤ 2.5 s | > 4.0 s |
| Cumulative Layout Shift (CLS) | How much the layout jumps while loading | ≤ 0.1 | > 0.25 |
| Total Blocking Time (TBT) | How long scripts block the page (lab stand-in for INP) | ≤ 200 ms | > 600 ms |
| First Contentful Paint (FCP) | When anything first appears | ≤ 1.8 s | > 3.0 s |
| Speed Index | How quickly the page fills in visually | ≤ 3.4 s | > 5.8 s |
| Server response time (TTFB) | How fast the server answers | ≤ 600 ms | > 1.8 s |
Google uses Core Web Vitals as part of its page experience signals. Interaction to Next Paint (INP) replaces First Input Delay in field data; in a lab test like this one, Total Blocking Time is the closest equivalent.
What is a good page speed score?
The Lighthouse performance score runs from 0 to 100: 90–100 is good, 50–89 needs improvement and below 50 is poor. Scores vary between runs by a few points because network and server conditions change, so test two or three times and focus on the metrics rather than the single score.
How to make your website faster
- Optimize images: serve WebP or AVIF, size them for the layout and lazy-load images below the fold.
- Reduce JavaScript: remove unused plugins and scripts, and defer what is not needed straight away.
- Eliminate render-blocking resources: inline critical CSS and load the rest asynchronously.
- Use caching and a CDN so pages are served close to visitors.
- Improve server response time with better hosting, page caching and fewer database calls.
- Reserve space for images, ads and embeds to prevent layout shift.
- Limit third-party tags such as chat widgets and trackers, which often add seconds on mobile.
Why page speed matters
Faster pages keep more visitors, convert better and make paid traffic cheaper by improving landing page experience. Speed is also part of Google’s page experience signals, and slow, unstable pages are harder for search engines and AI crawlers to process. Speed improvements pay off most on mobile, where networks and devices are slower.
Frequently asked questions
How do I test my website speed?
Paste the page URL into the speed test, choose mobile or desktop and click Test speed. You get a Lighthouse performance score, Core Web Vitals and a list of fixes.
What is a good website speed?
Aim for a Lighthouse performance score of 90 or more, Largest Contentful Paint under 2.5 seconds, Cumulative Layout Shift under 0.1 and Total Blocking Time under 200 milliseconds.
Why is my mobile score lower than desktop?
Mobile tests simulate a mid-range phone on a slower network, so heavy images and scripts have a bigger impact. Google mainly uses the mobile version of your site, so prioritize the mobile score.
Why does my score change each time I test?
Server load, network conditions and third-party scripts vary from run to run. Differences of a few points are normal; test several times and look at the trend.
Is this the same as Google PageSpeed Insights?
Both run Google Lighthouse lab tests, so results are comparable. PageSpeed Insights also shows field data from real Chrome users when enough data exists.
Is the website speed test free?
Yes. Enter your first name and email to see your results; we also email you a copy. There is a fair-use limit of a few tests per hour per visitor, and results for the same URL and device are cached for one hour.