How to Optimise Website Performance

Website performance optimisation reduces page load time and improves usability by tightening assets, code, caching, delivery, and server response to make pages usable faster.

If you have ever optimised only the homepage or chased micro-optimisations before fixing render-blocking scripts, you already know the biggest bottlenecks are the ones you ignore.

Key points

Measure a baseline with real-user data before changing anything, so you know which bottlenecks actually matter.
Compress images, serve responsive sizes, and use WebP or AVIF to cut file weight without visible quality loss.
Defer non-critical JavaScript and third-party scripts so they do not block initial page rendering.
Monitor performance continuously because plugins, scripts, and content can reintroduce slowdowns over time.

At a glance

Also called: Website speed optimisation, page speed optimisation, web optimisation
Lives in: Technical SEO, Core Web Vitals optimisation
Applies to: All web pages, especially content-heavy and e-commerce sites
Controlled by: Developers, hosting configuration, CMS settings

A homepage test that uncovered a 3-second TTFB

Despite previous website optimisation efforts, an e-commerce site’s homepage scored 45 on PageSpeed Insights. The team had minified CSS and combined images, but the real bottleneck was a slow database query. After moving to a faster host and adding a CDN, TTFB dropped from 3.2s to 0.4s, LCP from 6s to 2.1s, and conversion rate increased by 18%.

Three mistakes that waste performance effort

Oversized images Uploading a 4000px-wide photo and letting the browser resize it adds unnecessary kilobytes. Serve images at exact display dimensions instead.
Too many third-party scripts Each tracker, widget, or plugin adds network requests and blocks rendering. Audit and remove any that are not essential.
Lab-only optimisation Improving synthetic test scores without checking real-user metrics can miss bottlenecks like slow server response on mobile networks.

Three things to check before you start

Measure a baseline Use PageSpeed Insights or web.dev for a website speed test to get your Core Web Vitals and lab data. Know your current LCP, FID, and CLS.
Identify the biggest bottleneck Chrome DevTools or Lighthouse can show which resource, script, or server delay contributes most to load time, so you focus on the real bottleneck first.
Check your hosting Slow TTFB often comes from insufficient server capacity, database queries, or lack of a CDN. Upgrade before fine-tuning code for web optimisation.

Common questions

How to increase website speed WordPress without plugin?

Optimise images manually, minify CSS and JS in your theme, use a CDN, enable caching via .htaccess, and remove unused plugins.

How to improve website performance in React?

Use code splitting, lazy load components, memoize expensive computations, and minimise bundle size with tree shaking.

Sources

Google Search Central Official guidance on performance and Core Web Vitals for SEO.
web.dev Practical articles and tools for measuring and improving web performance.
Cloudflare Learning Center Explains caching, CDN, and TTFB optimisation.