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Core Web Vitals

What are Core Web Vitals?

Google introduced Core Web Vitals to guide developers and site owners in understanding the quality signals essential for delivering a great user experience on the web.



Core Web Vitals are a set of metrics from Google that help developers understand how users experience a web page. These tools were mainly introduced for developers; however, site owners should also take advantage of them because Core Web Vitals help break down the user’s real-world experience on a page.


The metrics that make up Core Web Vitals focus on loading, interactivity, and visual stability. They are known as the following:

GT Metrix Report
Largest Contentful Paint (LCP): The LCP metric measures the render time of the largest image or text block visible within the viewport relative to when the page started loading. Websites should attempt to have an LCP of 2.5 seconds or less to provide an optimal user experience. Read more about Largest Contentful Paint (LCP).
Pingdom Analytics Chart
First Input Delay (FID): The FID metric measures the time a user first interacts with a page (e.g. when they click a link or tap on a button, etc.) to the time when the browser can begin processing event handlers in response to that interaction. Websites should attempt to have a First Input Delay of 100 milliseconds or less to provide an optimal user experience. Read more about First Input Delay (FID).
Page speed Insights Data
Cumulative Layout Shift (CLS): The CLS metric measures the largest burst of layout shift scores for every unexpected layout shift that occurs during the entire lifespan of a page. A layout shift occurs whenever a visible element changes its position from one rendered frame to the next. Websites should attempt to have a Cumulative Layout Shift score of 0.1 or less to provide an optimal user experience. Read more about Cumulative Layout Shift (CLS).

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