Host Autopsy

Free Tool

Website Speed Optimization: The Complete 2026 Guide

Why your website is slow and exactly how to fix it. Core Web Vitals, image optimization, CDN setup, and more.

Speed Is Money

Amazon found that every 100ms of latency costs 1% in sales. Google uses page speed as a ranking factor. And 53% of mobile users abandon sites that take more than 3 seconds to load.

Core Web Vitals in 2026

Google's Core Web Vitals are the metrics that matter:

LCP (Largest Contentful Paint)

How long until the biggest visible element loads.

  • Good: Under 2.5 seconds
  • Needs work: 2.5 - 4 seconds
  • Poor: Over 4 seconds

INP (Interaction to Next Paint)

How quickly the page responds to user interactions.

  • Good: Under 200ms
  • Needs work: 200 - 500ms
  • Poor: Over 500ms

CLS (Cumulative Layout Shift)

How much the page layout jumps around during loading.

  • Good: Under 0.1
  • Needs work: 0.1 - 0.25
  • Poor: Over 0.25

The 5 Biggest Speed Killers

1. Unoptimized Images

Images are typically 50-70% of a page's total weight. Fix this:

  • Use WebP or AVIF format (30-50% smaller than JPEG)
  • Set explicit width/height attributes (prevents CLS)
  • Use responsive srcset for different screen sizes
  • Lazy-load below-the-fold images

2. Too Many HTTP Requests

Each resource (CSS file, JS file, font, image) requires a separate request. Reduce requests by:

  • Bundling CSS and JS
  • Using CSS sprites or SVG icons
  • Inlining critical CSS
  • Removing unused libraries

3. No CDN

A CDN (Content Delivery Network) serves your content from servers near your visitors. Without one, a user in Tokyo loads everything from your server in Virginia.

Top CDNs: Cloudflare (free tier), Fastly, AWS CloudFront, Vercel Edge Network.

4. Render-Blocking Resources

JavaScript and CSS in the <head> block page rendering. Fix with:

  • defer or async attributes on non-critical scripts
  • Inlining critical CSS and lazy-loading the rest
  • Moving third-party scripts (analytics, chat widgets) to load after the page

5. Slow Server Response (TTFB)

Time to First Byte over 600ms means your server is the bottleneck. Solutions:

  • Upgrade hosting (shared → VPS → dedicated)
  • Add server-side caching (Redis, Varnish)
  • Use a static site generator or edge rendering
  • Optimize database queries

Free Tools to Measure Speed

  1. Google PageSpeed Insights — Core Web Vitals from real users + lab data
  2. WebPageTest — Detailed waterfall charts and filmstrip view
  3. Chrome DevTools Lighthouse — Built into Chrome, run locally
  4. Host Autopsy Scanner — Our free tool checks speed plus security, DNS, SSL, and more

Run your site through our scanner above to get a comprehensive health check.

Check your own website

Run a free scan to check SSL, DNS, speed, and security headers.

Scan Your Site Free →