Understanding Core Web Vitals

Core Web Vitals are a set of specific factors that Google considers important in a webpage's overall user experience. They consist of three specific page speed and user interaction measurements: Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS).

Largest Contentful Paint (LCP)

LCP measures loading performance. To provide a good user experience, LCP should occur within 2.5 seconds of when the page first starts loading. This metric reports the render time of the largest image or text block visible within the viewport.

First Input Delay (FID)

FID measures interactivity. Pages should have an FID of 100 milliseconds or less. FID measures the time from when a user first interacts with a page to the time when the browser is actually able to begin processing event handlers in response to that interaction.

Cumulative Layout Shift (CLS)

CLS measures visual stability. Pages should maintain a CLS of 0.1 or less. CLS is a measure of the largest burst of layout shift scores for every unexpected layout shift that occurs during the entire lifespan of a page.

Why it matters

Google uses Core Web Vitals as ranking signals. Poor scores can directly impact your search rankings and user experience. Focus on optimizing images, reducing JavaScript execution time, and ensuring content stability to improve these metrics.