Why website speed directly affects your revenue
Google's research shows that for every additional second of load time, mobile bounce rates increase by 32%. A site that loads in one second converts 3x better than one that takes five. Since 2021, Core Web Vitals have been a direct Google ranking factor, meaning slow sites lose twice — once through lost conversions, and again through lower search visibility. A 90+ performance score isn't vanity; it is table stakes for competitive commercial sites.
The four scores and what they measure
- Performance — how fast content loads and becomes interactive. The hardest to move; requires image, font, JavaScript, and hosting optimisation.
- Accessibility — whether disabled users can use your site. Legal exposure plus ~15% of addressable market. Most gaps are quick wins.
- Best Practices — security, modern APIs, console errors. Usually 90+ with minor cleanup.
- SEO — on-page SEO basics: metadata, semantic HTML, mobile-friendliness. Not a complete SEO audit but a strong baseline.
A realistic optimisation playbook
First, fix the largest image on your page — compress it, convert to WebP/AVIF, and add width/height attributes. Second, defer or remove third-party scripts (chat widgets, analytics, heatmaps) that add blocking JavaScript. Third, preload your hero image and critical fonts. Fourth, add cache-control headers at your CDN. These four steps typically move most sites from a red performance score to amber, and from amber to green. After that, the real work begins: reducing main-thread JavaScript and eliminating layout shifts.