Speed is not just a number on a test. A useful website loads its main content promptly, responds when someone taps and keeps its layout steady while they read.
Start with the experience
Google describes three Core Web Vitals: Largest Contentful Paint measures loading, Interaction to Next Paint measures responsiveness and Cumulative Layout Shift measures visual stability. The recommended good thresholds are 2.5 seconds, 200 milliseconds and 0.1 respectively, assessed against real user data at the 75th percentile.
Make improvements people can feel
Optimise prominent images, avoid loading unnecessary code and reserve space for media. Check whether heavy scripts delay interactions, especially on mobile devices. Lab tests help reproduce issues; field data reveals what visitors actually experience.
What is new for single-page applications?
In October 2026, Chrome announced experimental CrUX measurements that include soft navigations. These are experimental, so treat them as an additional lens while continuing to monitor established metrics. A polished animation should support the experience rather than obscure content or slow interaction.
Sources & further reading
Reviewed 11 November 2026
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