A slow website can frustrate visitors, increase page abandonment, and reduce opportunities to generate enquiries or sales. Even if your website has excellent content and an attractive design, poor loading performance can affect how users experience your business.

Website speed optimisation is therefore an important part of website development and technical SEO. It helps pages load efficiently, respond quickly to user interactions, and remain visually stable while loading.

Google measures important aspects of user experience through Core Web Vitals. These metrics help website owners understand how visitors experience their pages and identify areas that need improvement.

In this guide, we will explain Core Web Vitals and share practical steps to improve website speed and performance.

What Are Core Web Vitals?

Core Web Vitals are a set of user experience metrics used by Google to evaluate loading performance, interactivity, and visual stability.

There are three main Core Web Vitals:

1. Largest Contentful Paint (LCP)

LCP measures how quickly the largest visible content element, such as a main image or heading, appears on the screen.

• Good: 2.5 seconds or less
• Needs improvement: More than 2.5 seconds and up to 4 seconds
• Poor: More than 4 seconds

2. Interaction to Next Paint (INP)

INP measures how quickly a page responds visually to user interactions, such as clicking a button or opening a menu.

• Good: 200 milliseconds or less
• Needs improvement: More than 200 milliseconds and up to 500 milliseconds
• Poor: More than 500 milliseconds

3. Cumulative Layout Shift (CLS)

CLS measures unexpected layout movement while a page loads. For example, a button suddenly moving because an image or advertisement loads late.

• Good: 0.1 or less
• Needs improvement: More than 0.1 and up to 0.25
• Poor: More than 0.25

Google recommends aiming for good results across all three metrics, measured at the 75th percentile of real user visits.

Step-by-Step Guide to Improve Website Speed and Core Web Vitals

Step 1: Test Your Website Performance

Before making changes, identify what is slowing down your website.

Use these tools:

• Google PageSpeed Insights: Measures performance and reports Core Web Vitals data when available.
• Google Search Console: Shows Core Web Vitals issues across groups of URLs.
• Chrome DevTools: Helps developers inspect loading behaviour, scripts, and layout shifts.

Start by testing your homepage and important service, product, or landing pages. Check both mobile and desktop performance.

Record the results before making changes so you can compare improvements later.

Step 2: Optimise Images

Large and uncompressed images are common reasons for slow website loading.

To improve image performance:

• Compress images before uploading them.
• Use modern formats such as WebP or AVIF where supported.
• Resize images according to their actual display dimensions.
• Add descriptive alt text to meaningful images.
• Use responsive images for different screen sizes.
• Enable lazy loading for images below the initial viewport.

Avoid lazy-loading the main image that determines your LCP. It should be discoverable and load promptly.

Image optimisation can reduce page weight without compromising visual quality.

Step 3: Improve Website Hosting and Server Response

Your hosting environment plays an important role in website performance. If the server takes too long to respond, visitors may experience delays before page content begins loading.

Consider these improvements:

• Choose reliable hosting suitable for your website traffic.
• Use a server location appropriate for your target audience.
• Upgrade resources if your website frequently experiences high server load.
• Enable server-side caching where appropriate.
• Use a Content Delivery Network (CDN) to serve content efficiently across locations.

Monitor Time to First Byte (TTFB) as a diagnostic metric. Although it is not a Core Web Vital, a slow server response can contribute to poor loading performance.

Step 4: Minify CSS, JavaScript, and HTML

Unnecessary code can increase the amount of data browsers need to download and process.

Minification removes unnecessary characters, spaces, and comments from code files without changing their functionality.

You can also:

• Remove unused CSS and JavaScript.
• Defer non-critical JavaScript.
• Load scripts only on pages where they are required.
• Avoid excessive third-party plugins and tracking scripts.

Be careful when combining or delaying scripts. Test important features such as menus, forms, checkout pages, and interactive elements after making changes.

Step 5: Enable Browser Caching

Browser caching allows returning visitors to reuse certain website resources instead of downloading everything again.

Configure suitable cache headers for static resources such as images, CSS, JavaScript, and fonts.

You can also use page caching on websites where content does not need to be generated dynamically for every visitor.

For WordPress websites, caching plugins can simplify some performance tasks. However, use compatible settings and test the website after configuration to avoid broken layouts or functionality.

Step 6: Improve Mobile Performance

A website that performs well on desktop may still be slow or difficult to use on mobile devices.

Mobile optimisation should be part of your overall speed strategy.

Focus on:

• Using responsive website layouts.
• Reducing large mobile images.
• Avoiding unnecessary pop-ups.
• Keeping navigation simple.
• Reducing heavy animations.
• Making buttons and links easy to tap.

Test your pages on different screen sizes and network conditions. Mobile users may have slower connections or less powerful devices, so lightweight pages can make a significant difference.

Step 7: Prevent Unexpected Layout Shifts

Unexpected movement can make a website difficult to use. For example, a visitor may try to click a button, but an advertisement or image loads and moves the button.

To reduce CLS:

• Set width and height attributes for images.
• Reserve space for advertisements and embedded content.
• Avoid inserting new content above existing content unexpectedly.
• Use suitable font-display settings.
• Ensure banners and pop-ups do not cause sudden layout changes.

A stable layout makes the browsing experience more comfortable and predictable.

Step 8: Reduce Unnecessary Third-Party Scripts

Third-party tools such as chat widgets, analytics scripts, advertising pixels, and social media embeds can affect website performance.

Review all external scripts and remove tools that are no longer needed.

Load non-essential scripts only when appropriate, and use asynchronous or deferred loading where supported.

Do not remove essential analytics or business features without checking their purpose. The goal is to keep useful functionality while reducing unnecessary processing.

How Do Core Web Vitals Affect SEO?

Core Web Vitals are part of Google’s page experience considerations. They can contribute to a better user experience, but achieving perfect scores does not guarantee higher search rankings.

Google also considers many other factors, including content relevance, usefulness, page accessibility, and overall search intent.

Therefore, website speed optimisation should support a broader SEO strategy rather than replace quality content and technical SEO fundamentals.

A fast, stable, and responsive website can also make it easier for visitors to explore services, complete forms, and make purchases.

Common Website Speed Optimisation Mistakes

Avoid these common mistakes when improving website performance:

• Installing multiple caching plugins that conflict with each other.
• Compressing images without checking their visual quality.
• Delaying important scripts that are required for page functionality.
• Lazy-loading images that should appear immediately.
• Ignoring mobile performance.
• Focusing only on PageSpeed scores instead of real user experience.
• Making changes without testing the website afterwards.

Optimisation should improve both performance and functionality.

Conclusion

Website speed optimisation is not just about achieving a high score in a testing tool. It is about creating a website that loads efficiently, responds quickly, and provides a stable experience across devices.

By optimising images, improving hosting, reducing unnecessary scripts, enabling caching, and fixing layout shifts, businesses can work towards better Core Web Vitals and a smoother user experience.

If your website is slow or struggling with performance issues, SEO WEB Technology can help you improve website performance through professional website development and technical SEO solutions.