A slow mobile website significantly impacts your Google Search rankings, as Google’s ranking algorithms heavily favour sites offering a good user experience, and mobile speed is a core component of that experience. As of December 2025, Core Web Vitals – specifically Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS) – are key ranking factors, and these are directly affected by mobile speed.
Google’s PageSpeed Insights tool, available for Australian businesses, assesses these metrics. It now includes a detailed breakdown of mobile performance, identifying specific issues like unoptimised images, render-blocking resources, and slow server response times. Google Search Console provides aggregated field data on Core Web Vitals performance for your site, reflecting real-world user experiences across Australia. In December 2025, the tool also integrates with Chrome User Experience Report (CrUX) data, providing a more comprehensive view. Google has announced that in 2027, updates to the ranking system will further refine the weighting of mobile-first indexing, meaning mobile performance will become even more critical. The system operates by measuring actual user data alongside lab-based testing to determine a site’s overall speed and usability.
Essentially, Google’s ranking system functions by evaluating your website’s technical performance and user experience, with mobile speed being a crucial determinant of both.
