Web Vitals

Web Vitals is an initiative by Google to provide unified guidance for quality signals that are essential to delivering a great user experience on the web.

Core Web Vitals

Core Web Vitals are the subset of Web Vitals that apply to all web pages, should be measured by all site owners. ach of the Core Web Vitals represents a distinct facet of the user experience, is measurable in the field, and reflects the real-world experience of a critical user-centric outcome.

The metrics that make up Core Web Vitals will evolve over time. The current set focuses on three aspects of the user experience—loading, interactivity, and visual stability.

• Largest Contentful Paint (LCP): measures loading performance. To provide a good user experience, LCP should occur within 2.5 seconds of when the page first starts loading.
• Interaction to Next Paint (INP): measures interactivity. To provide a good user experience, pages should have a INP of 200 milliseconds or less.
• Cumulative Layout Shift (CLS): measures visual stability. To provide a good user experience, pages should maintain a CLS of 0.1. or less.

LCP

• Represents how quickly the main content of a web page is loaded.
• The time from when the user initiates loading the page until the largest image or text block is rendered within the viewport.
• Threshold at 2.5s.
• To optimize, rather than looking at lab tools, real data from users should be collected.