Page Speed

The speed at which a web page loads and becomes usable, a confirmed ranking factor for both desktop and mobile search.

Page speed has been a Google ranking factor since 2010 for desktop and 2018 for mobile. In practical terms, Google measures page speed through Core Web Vitals (LCP, CLS, INP) using real-user Chrome data rather than synthetic lab tests. Tools like Google PageSpeed Insights provide both lab scores (Lighthouse) and field data (CrUX).

Page speed affects SEO both directly (as a ranking signal) and indirectly (through user experience metrics: bounce rate, session duration, conversion rate). Studies consistently show that even 100ms slowdowns reduce conversions, and pages that are 1s slower see ~7% fewer conversions.

Key optimisation areas: compress and serve images in modern formats (WebP/AVIF), remove unused CSS and JavaScript, defer non-critical JavaScript, use browser caching, implement a CDN, reduce server response time (TTFB), and eliminate render-blocking resources.

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Related SEO Terms

Core Web Vitals

Google's set of real-world performance metrics (LCP, CLS, INP) that me…

Largest Contentful Paint (LCP)

A Core Web Vital that measures how long the largest visible element ta…

Time to First Byte (TTFB)

The time between a browser requesting a page and receiving the first b…

Cumulative Layout Shift (CLS)

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