Website Performance & Core Web Vitals: Why Speed Matters for SEO and Conversions

Why Website Speed Matters

Website speed affects two critical business metrics:

SEO Rankings — Google considers page speed as a ranking factor
Conversions — Every 1-second delay in page load time can reduce conversions by 7%

A slow website is costing you customers and rankings.

Core Web Vitals: The Three Metrics That Matter

Google's Core Web Vitals are three metrics that measure user experience:

1. Largest Contentful Paint (LCP)

How long it takes for the main content to load. Target: Under 2.5 seconds.

2. First Input Delay (FID)

How responsive your site is to user interaction. Target: Under 100 milliseconds.

3. Cumulative Layout Shift (CLS)

How much the page layout shifts as it loads. Target: Under 0.1.

How to Optimise Core Web Vitals

Improve LCP (Page Load Speed)

1. Optimise Images

Compress images (use tools like TinyPNG)
Use modern formats (WebP instead of JPG)
Lazy load images (load only when visible)

2. Minimise CSS and JavaScript

Remove unused CSS
Defer non-critical JavaScript
Minify code

3. Use a Content Delivery Network (CDN)

CDNs cache your content on servers worldwide
Users download from the nearest server
Significantly improves load times

4. Upgrade Hosting

Shared hosting is slow
Consider managed WordPress hosting or cloud hosting
Better servers = faster load times

Improve FID (Responsiveness)

1. Reduce JavaScript Execution

Break up long JavaScript tasks
Defer non-critical JavaScript
Use web workers for heavy processing

2. Optimise Third-Party Scripts

Third-party scripts (analytics, ads, chat) can slow your site
Load them asynchronously
Consider removing non-essential scripts

Improve CLS (Visual Stability)

1. Set Image and Video Dimensions

Always specify width and height
Prevents layout shifts when images load

2. Avoid Inserting Content Above Existing Content

Don't insert ads or pop-ups at the top of the page
Users get frustrated when content shifts

3. Use CSS Transforms for Animations

CSS transforms don't trigger layout shifts
Avoid animating properties like width or height

Tools to Measure Website Speed

Google PageSpeed Insights

Free tool that measures Core Web Vitals and provides recommendations.

Google Lighthouse

Built into Chrome DevTools. Measures performance, accessibility, SEO, and best practices.

GTmetrix

Detailed performance analysis with waterfall charts and recommendations.

Quick Wins for Immediate Improvement

Enable GZIP compression — Reduces file sizes by 50-70%
Leverage browser caching — Browsers cache static files locally
Minify CSS and JavaScript — Remove unnecessary characters
Optimise images — Compress and use modern formats
Remove unused plugins — Each plugin adds overhead

The Bottom Line

Website speed is no longer optional—it's a ranking factor and a conversion factor. Optimise your Core Web Vitals and watch your rankings and conversions improve. Start with image optimisation and hosting upgrades for the biggest impact.