- Competitor Comparison
- AI Recommendations
- PageSpeed History
- Tech Stack Detection
Website Speed Test with AI Insights, Benchmark & Multi-Scan
Example report
sample.perfdelta.com
46
Mobile
79
Desktop
4.1 s
LCP
310 ms
INP
0.19
CLS
Sample data for a fictional domain, with every section a real report contains.
Run a free page speed test on any website and see how fast it really loads. PerfDelta measures several pages of your site for mobile and desktop and shows the results in your browser, usually in under a minute. You get the Core Web Vitals that Google uses to judge page experience, plus the lab metrics that reveal why a page is slow.
4,463
websites analyzed so far
500
free tests left today
See what counts as normal in your industry
Beyond a standard PageSpeed test
What gets measured
What this page speed test measures
A single score explains little, so the test keeps two kinds of data apart. Field data comes from real Chrome users and covers the Core Web Vitals: Largest Contentful Paint, Interaction to Next Paint and Cumulative Layout Shift. These are the values Google reads, so they matter for ranking. Lab data comes from a controlled Lighthouse run and explains the causes behind slow load times, such as server response time, Speed Index and blocking time. Seeing both tells you what your users experience and where the problem sits.
Core Web Vitals by metric
LCP
71% 23% 7%
INP
73% 25% 2%
CLS
74% 17% 10%
From 4,463 websites analyzed with PerfDelta
How it works
How the website speed test works
Enter your URL and start the test. A progress bar tracks each step while the tool finds your sitemap, picks a handful of different pages and measures them for mobile and desktop. When it finishes, the full report opens on screen. Every result gets its own link that stays live for 365 days, so you can bookmark it, send it to a developer or share it with a client. No account, no install. The test runs from the outside, the way a visitor and Google see your site.
Only 49% of 4,277 websites with field data pass all three Core Web Vitals.
PerfDelta measurements, recalculated daily · Website speed statistics
Where you stand
Benchmark and competitor comparison
The most interesting delta is the one between your site and your fastest competitor's.
Most tools stop at one number for one page. PerfDelta checks several page types and puts your Core Web Vitals next to the global benchmark. Only 49% of 4,277 websites with field data pass all three Core Web Vitals, so you see at a glance whether your site leads or trails. Add up to two competitor domains and the report places their real-user data beside yours.
Open the Core Web Vitals benchmark
Core Web Vitals pass rate
From 4,277 websites with field data, measured with PerfDelta
Speed also depends on what a site does: a shop with product imagery carries a different load than a doctor's practice with a contact page. The industry benchmarks group every domain tested with PerfDelta by industry and show what is actually normal in each one, including the platform split inside them.
Inside the report
What the report shows
Per page you get your field values with a clear pass or fail, and the biggest bottleneck across the site. The report breaks page weight down by JavaScript, images, CSS, fonts and HTML, and names the third-party scripts that cost the most, including how long they block the browser. Below that sit the lab metrics for every page, worst first. It is the fast, honest read that tells you where to start.
Technology stack of analyzed websites
Bubble size = number of websites, one colour per technology. Listed by average mobile performance score, weakest first.
- Angular 110 websites, avg. score 34
- Optimizely 60 websites, avg. score 34
- Akamai mPulse 109 websites, avg. score 34
- Boomerang 109 websites, avg. score 34
- Osano 44 websites, avg. score 34
- Akamai Bot Manager 109 websites, avg. score 34
- Salesforce Commerce Cloud 83 websites, avg. score 35
- Salesforce 40 websites, avg. score 35
- Akamai 217 websites, avg. score 36
- OpenResty 37 websites, avg. score 37
- Yotpo Reviews 35 websites, avg. score 37
- DoubleClick Floodlight 86 websites, avg. score 37
- Google Publisher Tag 98 websites, avg. score 38
- Node.js 43 websites, avg. score 38
- Express 40 websites, avg. score 38
- reCAPTCHA 106 websites, avg. score 38
- Envoy 137 websites, avg. score 38
- Imperva 79 websites, avg. score 39
- Adobe Experience Manager 335 websites, avg. score 39
- Dynatrace RUM 52 websites, avg. score 39
- Dynatrace 52 websites, avg. score 39
- YouTube 66 websites, avg. score 39
- React 683 websites, avg. score 40
- Google Maps 43 websites, avg. score 40
- Google Hosted Libraries 91 websites, avg. score 40
- Nuxt 41 websites, avg. score 40
- Material UI 32 websites, avg. score 40
- OWL Carousel 62 websites, avg. score 40
- Unpkg 55 websites, avg. score 40
- F5 BigIP 98 websites, avg. score 40
- Next.js 758 websites, avg. score 40
- Fourthwall 106 websites, avg. score 40
- OneTrust 290 websites, avg. score 41
- Java 287 websites, avg. score 41
- Contentful 160 websites, avg. score 41
- Adobe Fonts 153 websites, avg. score 41
- Typekit 153 websites, avg. score 41
- Google Cloud 89 websites, avg. score 41
- Slick 94 websites, avg. score 41
- Sanity 49 websites, avg. score 41
- jQuery UI 60 websites, avg. score 41
- Algolia 31 websites, avg. score 41
- Google Cloud CDN 78 websites, avg. score 42
- Nuxt.js 69 websites, avg. score 42
- Popper 50 websites, avg. score 42
- Cloudflare Browser Insights 40 websites, avg. score 42
- cdnjs 143 websites, avg. score 42
- Webflow 33 websites, avg. score 42
- Bootstrap 275 websites, avg. score 42
- Fastly 87 websites, avg. score 42
- Font Awesome 86 websites, avg. score 42
- Amazon CloudFront 482 websites, avg. score 42
- Shopify 294 websites, avg. score 42
- Klaviyo 109 websites, avg. score 42
- jQuery CDN 60 websites, avg. score 42
- Webpack 209 websites, avg. score 43
- Linkedin Insight Tag 186 websites, avg. score 43
- IIS 42 websites, avg. score 43
- Windows Server 42 websites, avg. score 43
- Amazon Web Services 679 websites, avg. score 43
- Skolengo 55 websites, avg. score 43
- Apache Tomcat 55 websites, avg. score 43
- jsDelivr 151 websites, avg. score 43
- ZURB Foundation 51 websites, avg. score 43
- Swiper 30 websites, avg. score 43
- Trustpilot 30 websites, avg. score 43
- Azure Front Door 73 websites, avg. score 43
- Amazon S3 238 websites, avg. score 43
- Linkedin Ads 121 websites, avg. score 43
- Vue.js 81 websites, avg. score 43
- Varnish 254 websites, avg. score 43
- Acquia Cloud Platform 50 websites, avg. score 44
- MariaDB 118 websites, avg. score 44
- Google Tag Manager 1252 websites, avg. score 44
- Gatsby 37 websites, avg. score 44
- Azure 118 websites, avg. score 44
- Tailwind CSS 59 websites, avg. score 44
- Azure Edge Network 34 websites, avg. score 44
- Microsoft ASP.NET 96 websites, avg. score 44
- HSTS 2221 websites, avg. score 44
- Vercel 97 websites, avg. score 44
- Pantheon 64 websites, avg. score 44
- Amazon ALB 32 websites, avg. score 45
- Cloudflare 1062 websites, avg. score 45
- jQuery 773 websites, avg. score 45
- Snowplow Analytics 36 websites, avg. score 45
- PayPal 47 websites, avg. score 45
- HTTP/3 1018 websites, avg. score 45
- Cloudflare Bot Management 278 websites, avg. score 45
- Sitecore 100 websites, avg. score 45
- Cookiebot 35 websites, avg. score 46
- Elementor 32 websites, avg. score 46
- Netlify 34 websites, avg. score 46
- Drupal 261 websites, avg. score 46
- Modernizr 76 websites, avg. score 46
- Google Analytics 312 websites, avg. score 46
- Alpine.js 43 websites, avg. score 47
- Apache HTTP Server 268 websites, avg. score 48
- Nginx 421 websites, avg. score 48
- Usercentrics 41 websites, avg. score 48
- Google AdSense 36 websites, avg. score 48
- WP Engine 55 websites, avg. score 49
- WordPress 466 websites, avg. score 49
- PHP 597 websites, avg. score 50
- jQuery Migrate 180 websites, avg. score 50
- MySQL 343 websites, avg. score 50
- Yoast SEO 178 websites, avg. score 51
- Yoast SEO Premium 72 websites, avg. score 51
- WordPress Block Editor 62 websites, avg. score 51
- WP Rocket 59 websites, avg. score 61
From 4,463 websites analyzed with PerfDelta
Speed and rankings
Why page speed matters for SEO
Speed is part of how Google ranks pages. The Core Web Vitals feed into its page experience signal, and slow pages lose visibility and conversions, most of all on mobile, where visitors leave quickly. One page speed test is a snapshot. The report adds the CrUX trend for your domain, week by week over up to six months of real Chrome data, so a regression shows up before your rankings slip. Check the numbers against Google PageSpeed Insights and Search Console and you work from evidence instead of guesswork.
Why speed matters
What usually slows a page down
Four causes show up again and again on slow sites: a slow server response before anything can load, unused JavaScript and CSS the browser downloads anyway, unoptimized images and web fonts, and render-blocking resources that delay the first paint. PerfDelta checks all four automatically and totals the potential savings across every page you test, so you know where to start instead of digging through a wall of numbers.
Mobile performance score distribution
From 4,463 websites analyzed with PerfDelta
For the three Google metrics behind these numbers, read our Core Web Vitals guide: it explains LCP, INP and CLS, the thresholds that count as good and the fixes that move them. Every PageSpeed recommendation has its own guide in the audit overview.
Page speed test vs. Google PageSpeed Insights
Google PageSpeed Insights is Google's free tool for checking how fast a single URL loads. PerfDelta runs on the same data: the PageSpeed Insights API with Lighthouse for the lab metrics and the Chrome UX Report for field data from real users, so the numbers line up. The difference is scope. PageSpeed Insights tests one address per run. PerfDelta picks several structurally different pages from your sitemap, tests each one on mobile and desktop and brings the results together in one report, next to the global benchmark and up to two competitors, with a link you can share. For a quick look at one page, PageSpeed Insights is enough. To see how a whole site performs, a page speed test across several pages tells you more.
FAQ
About the tool
How do I test my website speed?
Enter your URL, start the test and wait on the page. PerfDelta measures several pages for mobile and desktop and shows a full page speed test report in under a minute.
How is this different from Google PageSpeed Insights?
It uses the same data sources but tests several pages at once, benchmarks your Core Web Vitals against the global average and competitors, and gives you one shareable report instead of a single-page lookup.
Is the page speed test free?
Yes, on any website and without an account.
Can I share the result?
Yes. Each report has a link that stays available for 365 days.
How can I improve my page speed?
Start with the heaviest content and the third-party scripts that block the browser. The report ranks these so you fix the load time issues that move the needle first.
Can I test a local or staging site?
No. PerfDelta measures pages the way a real visitor or Google sees them, over the public internet. A site on localhost or behind a login is not reachable from outside, so test the live, public URL instead.
Data & tech
What are Core Web Vitals?
Three real-user metrics Google uses for page experience: Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability).
What do LCP and CLS mean, and what are the thresholds?
LCP is how long the largest element takes to appear, CLS measures unexpected layout movement. A page passes at LCP 2.5 seconds or less, INP 200 milliseconds or less, and CLS 0.1 or less.
Is there a difference between mobile and desktop results?
Often yes, especially on phones. Every page is measured for both, so you see where mobile falls behind.
Which page speed test is the most accurate?
It depends what you compare. Lab tools like Lighthouse give a repeatable score under fixed conditions. Field data from the Chrome UX Report shows what real visitors experience. PerfDelta shows both side by side instead of picking one.
Why does Time to First Byte (TTFB) matter?
TTFB measures how long the server takes to respond before anything can load. A slow TTFB delays every metric that comes after it, including LCP. PerfDelta reports it per page, so you can tell a server problem apart from a front-end one.
Do fonts and third-party scripts really slow a site down?
Often, yes. Custom fonts and scripts from ad networks, chat widgets, or analytics tools add extra requests and can block the browser while they load. The report names the heaviest ones and how long each blocks rendering.
What is the difference between PageSpeed Insights and Core Web Vitals?
PageSpeed Insights is the tool. Core Web Vitals are three of the metrics it reports, LCP, INP, and CLS, which Google also uses as a ranking signal. PerfDelta draws on the same underlying data as PageSpeed Insights.