Website speed test: how fast is your website?
Enter any URL and get a performance report with Core Web Vitals and prioritized fixes in seconds.
Why website speed matters
Website speed directly affects how users experience your site and how search engines rank it. A slow site frustrates visitors, increases bounce rates, and costs you conversions. Research consistently shows that every additional second of load time reduces conversions by 4.4% on average.
Google uses Core Web Vitals — Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), and Interaction to Next Paint (INP) — as ranking signals. Meeting the recommended thresholds gives your pages a measurable advantage in search results.
What affects website loading speed?
Images & media
Unoptimized images are the #1 cause of slow pages. Using modern formats (WebP, AVIF), lazy loading, and proper sizing can cut load times dramatically.
JavaScript & CSS
Render-blocking scripts delay page display. Minimizing, deferring, and code-splitting JavaScript reduces Total Blocking Time and improves interactivity.
Server response time
Slow Time to First Byte (TTFB) delays everything else. A CDN, server-side caching, and efficient backend code reduce TTFB significantly.
Third-party scripts
Analytics, chat widgets, ad tags, and social embeds each add network requests and JavaScript. Audit and lazy-load non-essential third-party code.
Core Web Vitals thresholds (2026)
| Metric | Good | Needs improvement | Poor |
|---|---|---|---|
| LCP (Largest Contentful Paint) | ≤ 2.5s | 2.5s – 4.0s | > 4.0s |
| INP (Interaction to Next Paint) | ≤ 200ms | 200ms – 500ms | > 500ms |
| CLS (Cumulative Layout Shift) | ≤ 0.1 | 0.1 – 0.25 | > 0.25 |
Frequently asked questions
- How does this website speed test work?
- This tool uses the Google PageSpeed Insights API, which runs a full Lighthouse audit on your URL. It measures real-world performance metrics including Core Web Vitals, then returns scored results with prioritized optimization recommendations.
- What is a good website speed score?
- A performance score of 90–100 is considered good, 50–89 needs improvement, and 0–49 is poor. For Core Web Vitals, Google recommends LCP under 2.5 seconds, CLS under 0.1, and INP under 200 milliseconds.
- Why is my mobile score lower than desktop?
- Mobile scores are typically lower because Lighthouse simulates a mid-tier mobile device on a slower network connection. This reflects real-world conditions for most mobile users. Desktop tests assume a faster device and network.
- How can I improve my website speed?
- The most impactful improvements are: optimize images with modern formats (WebP, AVIF), minimize and defer JavaScript, use a CDN, enable browser caching, and reduce server response time. This tool shows your specific opportunities sorted by impact.
- Does website speed affect SEO rankings?
- Yes. Google uses Core Web Vitals as a ranking signal. Sites meeting the recommended thresholds get a ranking boost. Beyond SEO, faster sites have lower bounce rates and higher conversion rates — a 1-second delay can reduce conversions by up to 7%.
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