Page speed measures how quickly your website loads and becomes usable. It is a Google ranking factor and directly impacts user experience. Key metrics include Time to First Byte (TTFB), Largest Contentful Paint (LCP), and Time to Interactive. Faster sites rank better and convert more visitors.
Page speed measures how quickly your website loads and becomes usable. It is a Google ranking factor and directly impacts user experience. Key metrics include Time to First Byte (TTFB), Largest Contentful Paint (LCP), and Time to Interactive. Faster sites rank better and convert more visitors.
Why Page Speed Matters
SEO Impact
Page speed is a confirmed ranking factor.
Google’s position:
- Speed factor since 2010 (desktop)
- Speed factor since 2018 (mobile)
- Core Web Vitals factor since 2021
User Experience Impact
| Load Time | Bounce Rate Impact |
|---|---|
| 1-3 seconds | 32% increase |
| 1-5 seconds | 90% increase |
| 1-6 seconds | 106% increase |
| 1-10 seconds | 123% increase |
Business Impact
- Higher conversion rates
- Better engagement metrics
- Improved customer satisfaction
- Lower bounce rates
Page Speed Metrics
Time to First Byte (TTFB)
Time until browser receives first byte from server.
Good TTFB: Under 600ms Affected by: Server performance, CDN, caching
First Contentful Paint (FCP)
Time until first content renders on screen.
Good FCP: Under 1.8 seconds Affected by: Render-blocking resources, server response
Largest Contentful Paint (LCP)
Time until largest content element loads.
Good LCP: Under 2.5 seconds Affected by: Images, server response, client-side rendering
See Core Web Vitals for detailed LCP optimization.
Speed Index
How quickly content is visually displayed.
Good Speed Index: Under 3.4 seconds
Time to Interactive (TTI)
Time until page is fully interactive.
Good TTI: Under 3.8 seconds Affected by: JavaScript execution, main thread blocking
Speed Optimization Techniques
Server Optimization
Improve TTFB:
1. Use quality hosting
2. Implement server-side caching
3. Use CDN for static assets
4. Optimize database queries
5. Enable HTTP/2 or HTTP/3
6. Use edge computing where beneficial
Image Optimization
Images are usually the largest files on a page.
| Technique | Impact |
|---|---|
| Compression | 50-80% size reduction |
| Modern formats (WebP, AVIF) | 25-50% smaller than JPEG |
| Responsive images | Serve appropriate sizes |
| Lazy loading | Defer off-screen images |
Image optimization checklist:
- Compress all images
- Use WebP with JPEG fallback
- Implement srcset for responsive images
- Lazy load below-fold images
- Set explicit dimensions
CSS Optimization
Techniques:
- Minify CSS files
- Remove unused CSS
- Inline critical CSS
- Defer non-critical CSS
- Avoid @import
Critical CSS example:
<head>
<style>
/* Inline critical above-fold styles */
.header { ... }
.hero { ... }
</style>
<link rel="preload" href="styles.css" as="style" onload="this.rel='stylesheet'">
</head>
JavaScript Optimization
Techniques:
- Minify JavaScript
- Remove unused code
- Defer non-critical scripts
- Use async for independent scripts
- Code split large bundles
<!-- Defer non-critical JS -->
<script defer src="analytics.js"></script>
<!-- Async for independent scripts -->
<script async src="chat-widget.js"></script>
Caching
Leverage browser caching for returning visitors.
Cache-Control headers:
# Static assets (1 year)
Cache-Control: public, max-age=31536000
# HTML (revalidate)
Cache-Control: no-cache
Compression
Enable text compression for faster transfer.
Compression options:
- Brotli (best compression)
- Gzip (wider support)
Resource Hints
Preload critical resources.
<!-- Preload critical font -->
<link rel="preload" href="font.woff2" as="font" crossorigin>
<!-- Preload LCP image -->
<link rel="preload" href="hero.webp" as="image">
<!-- DNS prefetch for third parties -->
<link rel="dns-prefetch" href="//cdn.example.com">
<!-- Preconnect to critical origins -->
<link rel="preconnect" href="https://fonts.googleapis.com">
Measuring Page Speed
Google Tools
| Tool | Purpose | Data Type |
|---|---|---|
| PageSpeed Insights | Detailed analysis | Lab + Field |
| Search Console | Site-wide issues | Field |
| Lighthouse | Technical audit | Lab |
| Chrome DevTools | Debugging | Lab |
Third-Party Tools
- WebPageTest (detailed waterfall)
- GTmetrix (historical tracking)
- Pingdom (uptime + speed)
Real User Monitoring (RUM)
Track actual user experience.
RUM options:
- Chrome User Experience Report
- Google Analytics Web Vitals
- Third-party RUM tools
Speed Optimization Checklist
Server
- Quality hosting provider
- CDN for static assets
- Server-side caching
- HTTP/2 enabled
- TTFB under 600ms
Images
- All images compressed
- WebP format used
- Responsive images (srcset)
- Lazy loading implemented
- Explicit dimensions set
Code
- CSS minified
- JavaScript minified
- Unused code removed
- Critical CSS inlined
- Non-critical JS deferred
Caching
- Browser caching configured
- Cache headers optimized
- Service worker (if applicable)
Delivery
- Compression enabled (Brotli/Gzip)
- Resource hints used
- Third-party scripts audited
- Render-blocking eliminated
Common Speed Mistakes
- Unoptimized images - Largest impact on load time
- No caching - Every visit loads fresh
- Render-blocking resources - Delays first paint
- Too many HTTP requests - Each request adds latency
- Heavy third-party scripts - Analytics, ads, widgets
- No CDN - Distance affects latency
- Unminified code - Larger file transfers
Conclusion
Page speed directly impacts SEO rankings, user experience, and business metrics. Faster sites rank better, engage users more, and convert at higher rates.
Start with the biggest impact items: optimize images, enable caching, and eliminate render-blocking resources. Use PageSpeed Insights to identify specific issues and track improvements.
Combine page speed optimization with Core Web Vitals targets for comprehensive performance. Regular monitoring ensures speed doesn’t degrade as your site evolves.