Website Speed Test – Free Real-Time Core Web Vitals & Performance Audit
Test website speed and analyze Core Web Vitals (LCP, FID, INP, CLS, TTFB) in real time. Diagnose render-blocking scripts, uncompressed images, server response times, HTTP/2 & Brotli compression, and page weight waterfalls with actionable recommendations for Mobile and Desktop.
How to use Website Speed Test Online
- Step 1: Enter any website URL (e.g. example.com or https://mysite.com) in the audit input bar.
- Step 2: Select your target testing strategy: Mobile (simulated 4G on mid-tier mobile hardware) or Desktop (high-speed broadband connection).
- Step 3: Click "Run Speed Audit" to initiate real-time server TTFB measurement, asset analysis, and Core Web Vitals audit.
- Step 4: Inspect your Overall Performance Score (0-100) and Core Web Vitals gauges (LCP, FCP, CLS, TBT, Speed Index).
- Step 5: Review the visual Rendering Filmstrip timeline to pinpoint when the first visual paint and largest contentful elements appear.
- Step 6: Examine Prioritized Opportunities to eliminate render-blocking CSS/JS, optimize images to modern WebP/AVIF formats, and configure caching headers.
- Step 7: Download your executive PDF Speed Audit Report, export raw JSON diagnostics, or benchmark side-by-side with competitors.
Frequently Asked Questions
What is a good Website Speed Test score?
According to Google Lighthouse and Core Web Vitals standards, a score of 90 to 100 is considered Good (Fast), 50 to 89 Needs Improvement (Average), and below 50 is classified as Poor (Slow). Google prioritizes websites achieving "Good" Core Web Vitals for search rankings and mobile search discoverability.
What are Core Web Vitals and why do they impact SEO rankings?
Core Web Vitals are a set of real-world, user-centric performance metrics established by Google. They measure three essential facets of web page experience: Largest Contentful Paint (LCP) for loading speed (target: ≤ 2.5s), Interaction to Next Paint (INP) / First Input Delay (FID) for responsiveness (target: ≤ 200ms), and Cumulative Layout Shift (CLS) for visual stability (target: ≤ 0.1). Passing Core Web Vitals is an official Google search ranking factor.
What is Time to First Byte (TTFB) and how do I optimize it?
Time to First Byte (TTFB) measures the duration from when a user's browser sends an HTTP request to when it receives the first byte of data from the web server. A good TTFB is under 200-500ms. High TTFB is typically caused by slow database queries, lack of server-side page caching, shared hosting CPU limits, or absence of a global Content Delivery Network (CDN) like Cloudflare, Fastly, or CloudFront.
Why does mobile performance score usually score lower than desktop?
Mobile audits simulate standard mid-tier smartphones (such as a Moto G Power) over throttled 4G network conditions. Mobile devices have slower CPU processing power to parse heavy JavaScript bundles and render CSS, whereas desktop tests simulate unthrottled high-speed broadband connections on multi-core workstation processors.
What causes render-blocking resources and how do I fix them?
Render-blocking resources are external `<script>` and `<link rel="stylesheet">` tags in the HTML `<head>` that prevent the browser from rendering visual page elements until they are completely downloaded and parsed. You can fix them by adding `defer` or `async` attributes to non-critical scripts, inlining critical above-the-fold CSS, and lazy-loading secondary stylesheets.
How does page load speed impact eCommerce conversion rates?
Extensive studies by Google, Amazon, and Akamai demonstrate that every 100ms increase in page latency decreases conversion rates by up to 7%. Furthermore, pages taking longer than 3 seconds to load suffer from a 53% mobile abandonment rate. Fast websites enjoy higher engagement, lower bounce rates, and superior organic keyword rankings.
How do images affect Cumulative Layout Shift (CLS)?
When `<img>` tags lack explicit `width` and `height` (or aspect-ratio) attributes in HTML or CSS, the browser cannot reserve the necessary layout space prior to downloading the image. As the image loads, content below it abruptly jumps downward, frustrating users and creating severe CLS penalties.
Is this Website Speed Test tool completely free?
Yes, 100% free with unlimited audits, zero watermarks, no account registration required, and full export capabilities including professional PDF audit reports and side-by-side competitor benchmarking.