Website Speed Optimisation
Faster websites rank higher, convert better, and keep visitors engaged.
Site speed is one of the most impactful and most overlooked improvements a business can make. We audit, diagnose, and fix performance issues across WordPress, Astro, and custom-built websites.
The Impact
The real cost of slow pages
Why Website Speed Matters
Page speed affects every measurable outcome for your website: how many people find it, how long they stay, and how many of them become customers.
SEO Rankings
Google uses Core Web Vitals as a ranking signal. Slow pages are penalised in search results, meaning a sluggish site is actively losing organic traffic to faster competitors. Page speed has been a direct ranking factor since Google's Page Experience update, and its influence has grown with every algorithm update since.
Conversion Rates
Every extra second of load time erodes user confidence and patience. Studies consistently show that a one-second delay reduces conversions by around 7%. For a site generating 100 enquiries a month, that is 7 leads lost - per second of unnecessary delay. Speed is one of the highest-ROI optimisations available for any website with commercial intent.
User Experience
Speed is experience. A slow site feels untrustworthy, frustrating, and outdated regardless of how good it looks. 53% of mobile visitors abandon a page that takes more than 3 seconds to load. Bounce rate, time on site, pages per session - every engagement metric improves when pages load fast and respond instantly.
What Are Google Core Web Vitals?
Core Web Vitals are a set of specific, measurable metrics that Google uses to quantify user experience on the web. They focus on three dimensions of performance: loading speed, visual stability, and interactivity. Google measures these from real Chrome users visiting your pages (field data) as well as from lab simulations (Lighthouse).
Largest Contentful Paint
Measures how long it takes for the largest visible element on the page - typically the hero image or main heading - to fully load and render. LCP is the primary measure of perceived loading speed.
Common causes: unoptimised images, slow server response, render-blocking resources.
Interaction to Next Paint
Measures the delay between a user interacting with the page - clicking a button, tapping a link, typing in a field - and the browser visually responding. Replaced FID (First Input Delay) in March 2024. INP captures the full range of interactions across the user's visit, not just the first one.
Common causes: heavy JavaScript execution, long tasks blocking the main thread.
Cumulative Layout Shift
Measures unexpected movement of visible content as the page loads. The jarring experience of going to click a button only for an image or ad to load and push it out of reach. CLS scores the total amount of layout instability across the page's lifetime. Low CLS means a visually stable, predictable page.
Common causes: images without dimensions, late-loading ads, web fonts that swap on load.
How Google Measures Web Vitals
Field Data (Real User Monitoring)
Google collects Web Vitals from real Chrome users visiting your pages and aggregates this into the Chrome User Experience Report (CrUX). This field data is what Google actually uses for ranking. It reflects real-world conditions including slow devices, poor connections, and browser extensions. You can see your field data in Google Search Console under Core Web Vitals, and in PageSpeed Insights.
Lab Data (Lighthouse Simulations)
Lighthouse runs controlled simulations of your page on a standardised throttled connection and device profile. Lab data is useful for diagnosing and fixing issues because it is consistent and reproducible. It is the score shown in Google PageSpeed Insights, Chrome DevTools, and web.dev. Lab scores and field scores often differ - a page can score 90+ in Lighthouse but still have poor field data if the real user base is on slow mobile connections.
Our Approach
What We Optimise
A speed audit covers every layer of the stack, from server configuration and image delivery through to JavaScript execution and third-party script management.
Image Optimisation
Images are the single biggest contributor to slow load times on most sites. We convert images to modern formats like WebP and AVIF, apply responsive sizing so browsers only download what they need, and implement lazy loading for images below the fold.
Server Response Time (TTFB)
Time to First Byte measures how quickly the server starts responding. We identify slow hosting, misconfigured caching layers, and unoptimised database queries that inflate TTFB and delay every subsequent step of page loading.
Caching Strategy
Static assets should be served from cache, not regenerated on every request. We configure browser caching, CDN caching, and server-side caching to ensure repeat visitors and geographically distant users get fast responses.
JavaScript Reduction and Deferral
JavaScript is the most common cause of slow interactivity. We audit what is loaded, remove unused code, split bundles, and defer or async-load scripts that are not needed for the initial render so the main thread stays free.
CSS and Font Delivery
Render-blocking CSS and web fonts delay the first paint of your page. We inline critical CSS, preload key fonts, use font-display swap to prevent invisible text, and remove unused stylesheets.
Core Web Vitals Fixes
Targeted fixes for LCP, INP, and CLS failures: preloading the LCP image, setting explicit dimensions on media, reducing long tasks, and stabilising layout during load. We address the specific issues that affect your real-user field data.
Speed vs Third-Party Tracking Scripts
One of the most honest conversations in site speed work is about third-party scripts. The same tools that power your marketing - Google Analytics, Google Ads conversion tracking, Meta Pixel, LinkedIn Insight, CRM chat widgets, heatmap tools - all add to the weight of code the browser must download, parse, and execute on every page load.
The Problem With Third-Party Scripts
- + Each script makes one or more external network requests to servers you do not control, with latency you cannot optimise.
- + Scripts from Google, Meta, and third-party vendors run on the browser's main thread, competing directly with your own code and increasing INP scores.
- + A single chat widget or session recording tool can add 100KB or more of JavaScript - equivalent to the rest of a well-optimised page combined.
- + Many scripts load additional scripts of their own. A tag manager implementation that fires 12 tags can generate 30 or more external requests.
How We Manage the Tradeoffs
- + Script auditing: We review every tag firing on your site and identify scripts that are duplicated, unused, or can be removed without losing meaningful data.
- + Deferred loading: Non-critical scripts - chat widgets, heatmaps, affiliate trackers - are deferred until after the main page content has loaded so they do not block rendering.
- + Server-side tracking: For conversion events where possible, we can route data through server-side Tag Manager rather than client-side scripts, reducing browser payload significantly.
- + Honest prioritisation: We help you weigh the value of each tracking tool against its performance cost. Some scripts are worth the overhead; others are not.
The honest truth about perfect Lighthouse scores
A site running Google Analytics, a Google Ads conversion tag, Meta Pixel, and a live chat widget will never score 100 on Lighthouse, no matter how well everything else is optimised. That is not a failure. The goal is not the highest possible number in isolation - it is the fastest possible site that still provides the data and tools your business depends on. We help you find that balance, make every possible gain within those constraints, and be clear about what the remaining cost is and why it is justified.
Find out what is slowing your website down
We will audit your site, identify the biggest performance wins, and give you a clear plan to improve your Core Web Vitals, rankings, and conversion rate.