Website Speed Test

Measure load time, TTFB, resource breakdown, and get optimization recommendations for any website.

Waterfall Chart Core Web Vitals Optimization Tips Performance Grade Resource Breakdown

Understanding Website Performance

Learn about performance metrics, optimization techniques, and how to make your website lightning-fast.

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Core Web Vitals Explained

Google's Core Web Vitals measure user experience: LCP (loading performance < 2.5s), FID (interactivity < 100ms), and CLS (visual stability < 0.1). These metrics directly impact SEO rankings and conversion rates.

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TTFB: First Performance Signal

Time To First Byte (TTFB) measures server response speed — the time between browser request and first byte received. Excellent TTFB is < 200ms. Slow TTFB indicates server issues or database problems. Optimize with caching, CDNs, and faster hosting.

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Waterfall Chart Analysis

Waterfall charts visualize every resource's loading timeline, showing DNS lookups, SSL handshakes, server wait times, and download durations. Identify slow resources, render-blocking scripts, and optimization opportunities.

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Modern Image Formats

WebP provides 25–35% better compression than JPEG/PNG. AVIF offers up to 50% smaller files with superior quality. Use modern formats with fallbacks, and always optimize and compress images before serving.

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Compression Techniques

Gzip compresses text files by 60–80%, reducing bandwidth and load times. Brotli offers 15–25% better compression than gzip for HTML/CSS/JavaScript. Enable compression on your server for all text-based resources.

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Browser Caching Strategy

Cache-Control and Expires headers tell browsers how long to cache resources. Use long max-age (1 year) for static assets with versioned filenames. Proper caching reduces server load and speeds up repeat visits.

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HTTP/2 and HTTP/3 Benefits

HTTP/2 enables multiplexing (multiple requests over one connection), header compression, and server push. HTTP/3 uses QUIC protocol for even better performance on unreliable networks. Upgrade your server to support modern protocols.

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Content Delivery Networks

CDNs distribute your content across global edge servers, serving files from locations closest to users. This reduces latency, improves load times, and provides DDoS protection. Popular CDNs: Cloudflare, CloudFront, Fastly.

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Render-Blocking Resources

CSS and JavaScript files that block rendering slow down FCP and LCP. Critical CSS should be inlined, non-critical CSS loaded asynchronously. Use async or defer for JavaScript, and split code into chunks.

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Speed Impacts Business

Studies show that a 1 second delay in page load time reduces conversions by 7%. Amazon found every 100ms of latency cost them 1% in sales. Google discovered that 53% of mobile users abandon sites that take longer than 3 seconds to load.

Frequently Asked Questions

How does the website speed test work? expand_more

Our speed test loads your website in a headless browser and captures a complete HAR (HTTP Archive) of all network requests. It measures Core Web Vitals (LCP, FCP, TTFB), captures timing phases for each resource, and analyzes performance against 7 best-practice categories to produce an overall grade.

What is TTFB and why does it matter? expand_more

Time To First Byte (TTFB) is the time between the browser sending a request and receiving the first byte of the response. It reflects your server response time. A good TTFB is under 200ms. High TTFB indicates slow server-side processing, database queries, or lack of caching.

What are Core Web Vitals? expand_more

Core Web Vitals are Google's metrics for user experience: LCP (Largest Contentful Paint — loading, < 2.5s), FID (First Input Delay — interactivity, < 100ms), and CLS (Cumulative Layout Shift — visual stability, < 0.1). These directly affect Google search rankings.

What does the waterfall chart show? expand_more

The waterfall chart shows every resource loaded by the page (HTML, CSS, JS, images, fonts) as a horizontal bar. Each bar is colored by phase: DNS (pink), Connect (blue), SSL (purple), Send (orange), Wait (yellow), Receive (green). Long Wait segments indicate slow server responses; long Receive segments indicate large files.

How is the performance grade calculated? expand_more

The grade (A–F) is based on a weighted score across 7 categories: Caching (25%), Compression (20%), Images (15%), Network (15%), Performance (15%), Resources (5%), and Security (5%). Grade A = 90–100, B = 80–89, C = 70–79, D = 60–69, E = 50–59, F = 0–49.

How can I improve my website speed? expand_more

Start with the Critical and High priority recommendations in the results. Common wins: enable GZIP/Brotli compression, set proper Cache-Control headers, optimize images (WebP, lazy loading), defer non-critical JavaScript, use a CDN, and reduce TTFB by upgrading hosting or adding server-side caching.

How long does the speed test take? expand_more

The test typically completes in 15–60 seconds depending on the complexity of the website. The browser needs to load all resources, run JavaScript, and capture complete timing data. Results are shareable via a permanent URL.