Website Speed Test
Analyze page load performance with Core Web Vitals (LCP, FCP, TTFB), waterfall charts, and optimization recommendations.
Understanding Website Performance
Learn about performance metrics, optimization techniques, and how to make your website lightning-fast.
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. Good scores mean faster, more responsive sites that users love.
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, inefficient backend code, or database problems. Optimize with caching, CDNs, and faster hosting.
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. Long wait times mean server issues; long download times mean large files.
HTTP Archive (HAR) Format
HAR files capture complete browser-server interactions in JSON format, including all requests, responses, headers, timing data, and caching information. Use HAR files for detailed debugging, sharing performance data with developers, and analyzing complex loading scenarios.
Modern Image Formats
WebP provides 25-35% better compression than JPEG/PNG while maintaining quality. AVIF offers even better compression (up to 50% smaller) with superior quality. Use modern formats with fallbacks: browsers that don't support them will use JPEG/PNG. Always optimize and compress images.
HTTP/2 and HTTP/3 Benefits
HTTP/2 enables multiplexing (multiple requests over one connection), header compression, and server push - dramatically faster than HTTP/1.1. HTTP/3 uses QUIC protocol for even better performance on unreliable networks. Upgrade your server to support modern protocols.
Compression Techniques
Gzip compresses text files by 60-80%, reducing bandwidth and load times. Brotli offers 15-25% better compression than gzip, especially for HTML/CSS/JavaScript. Enable compression on your server for all text-based resources. Check Accept-Encoding headers.
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. Set appropriate caching for HTML (short), CSS/JS (medium-long), and images/fonts (long). Proper caching reduces server load and speeds up repeat visits.
Minimize Redirects
Each redirect adds 200-600ms latency from DNS lookup, connection, and server processing. Common issues: www to non-www redirects, HTTP to HTTPS redirects, mobile redirects. Use direct URLs in links, update canonicals, and configure servers to avoid redirect chains.
Render-Blocking Resources
CSS and JavaScript files that block page rendering slow down FCP and LCP. Critical CSS should be inlined, non-critical CSS should be loaded asynchronously. Use async or defer for JavaScript. Split code into chunks, load above-the-fold content first.
Content Delivery Networks
CDNs distribute your content across global edge servers, serving files from locations closest to users. This reduces latency, improves load times, handles traffic spikes, and provides DDoS protection. Popular CDNs: Cloudflare, CloudFront, Fastly, Akamai.
Mobile Performance Matters
Mobile devices have slower CPUs, less memory, and often unreliable networks. Google uses mobile-first indexing - mobile performance determines rankings. Test with throttled 3G/4G connections. Optimize for mobile: reduce JavaScript, lazy load images, minimize main thread work.
Speed Impacts Business
Studies show that 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. Fast sites rank higher, convert better, and provide superior user experience.
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Frequently Asked Questions
Common questions about website speed testing, Core Web Vitals, and performance optimization
A website speed test measures how fast your website loads by analyzing load times, resource sizes, and performance metrics like TTFB (Time To First Byte), FCP (First Contentful Paint), and LCP (Largest Contentful Paint). Speed tests help identify bottlenecks, optimize performance, and improve user experience and SEO rankings.
Core Web Vitals are Google's key performance metrics: LCP (Largest Contentful Paint) measures loading performance, FID (First Input Delay) measures interactivity, and CLS (Cumulative Layout Shift) measures visual stability. Google uses these metrics as ranking factors. Good scores improve SEO, user experience, and conversion rates.
TTFB (Time To First Byte) is the time between a browser request and receiving the first byte of data from the server. Good TTFB is under 200ms. Improve it by: using a CDN, enabling server caching, optimizing database queries, upgrading hosting, enabling compression (gzip/brotli), and reducing server processing time.
A waterfall chart visualizes the loading timeline of all resources (HTML, CSS, JavaScript, images, fonts) on your webpage. Each bar shows when a resource started loading, how long it took, and what caused delays (DNS lookup, SSL handshake, server wait time). It helps identify slow resources and optimization opportunities.
HAR (HTTP Archive) is a JSON format for recording browser-server interactions. It captures detailed performance data including request/response headers, timing information, resource sizes, and caching behavior. HAR files are used for debugging, performance analysis, and sharing test results with developers.
Page speed is a direct Google ranking factor since 2010 (desktop) and 2018 (mobile). Faster sites rank higher, especially for mobile searches. Google's Core Web Vitals (LCP, FID, CLS) are official ranking signals. Slow sites have higher bounce rates, lower dwell time, and worse user signals, all harming SEO.
FCP (First Contentful Paint) measures when the first content appears (< 1.8s is good). LCP (Largest Contentful Paint) measures when the main content loads (< 2.5s is good). FID (First Input Delay) measures interactivity - time until the page responds to user input (< 100ms is good). All are Core Web Vitals.
Key optimizations: 1) Enable compression (gzip/brotli), 2) Optimize images (use WebP/AVIF, compress, lazy load), 3) Minify CSS/JavaScript, 4) Enable browser caching with long max-age, 5) Use a CDN, 6) Upgrade to HTTP/2 or HTTP/3, 7) Reduce redirects, 8) Eliminate render-blocking resources, 9) Use server-side caching.
Industry standards: < 2 seconds is excellent, 2-3 seconds is good, 3-5 seconds is average, > 5 seconds is poor. Mobile users expect even faster loads. Google recommends LCP < 2.5s, FCP < 1.8s, TTFB < 200ms. Amazon found that every 100ms of latency cost them 1% in sales. Speed directly impacts conversions.
Yes! HTTP/2 enables multiplexing (multiple requests over one connection), header compression, and server push - significantly faster than HTTP/1.1. HTTP/3 uses QUIC protocol for even better performance on lossy networks. Modern browsers support both. Check your server configuration and enable HTTP/2 or HTTP/3 for optimal speed.
Use modern formats: WebP provides 25-35% smaller file sizes than JPEG with similar quality. AVIF offers even better compression (up to 50% smaller than JPEG) but has limited browser support. For compatibility, serve WebP/AVIF with JPEG/PNG fallbacks using <picture> element. Always compress images before uploading.
Mobile and desktop speeds differ significantly due to network conditions, device capabilities, and rendering engines. Test both using tools that simulate mobile devices with throttled connections (3G/4G). Mobile-first indexing means Google primarily uses mobile performance for rankings. Prioritize mobile optimization.
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