Core Web Vitals Assessment
There’s not enough traffic to generate a report right now. Check again as your traffic increases or view the report for the entire domain.
Largest Contentful Paint
Time when the largest image, video or text element was painted to the screen. Learn more about Largest Contentful Paint (LCP).
Cumulative Layout Shift
Sum of scores of the unstable elements that move around during user sessions. Learn more about Cumulative Layout Shift (CLS).
First Input Delay
Time from first user interaction to the time when the browser can respond to the interaction. Learn more about First Input Delay (FID).
Other Notable Metrics
These metrics are not categorised as Core Web Vitals but are worth tracking to ensure a good user experience.
Time to First Byte
The time taken from the request being made until the first byte arriving back to the browser. Learn more about Time to First Byte (TTFB).
Interaction to Next Paint (Experimental)
The longest observed delay between user interaction and the browsers response on your page. Learn more about Interaction to Next Paint (Experimental) (INP).
First Contentful Paint
Time when the browser rendered any text, image, non-white canvas or SVG content. Learn more about First Contentful Paint (FCP).
Common questions
Where does this data come from?
Your summary is generated based on Google’s Chrome User Experience Report (CrUX)—a public dataset of real user experiences for millions of websites. CrUX collects data only for Chrome browser users who opted in (excluding devices with the iOS operating system). The set is updated daily and aggregates the previous 28 days of data.
How do I read this report?
The Core Web Vitals Assessment section shows if your page or site passes the Core Web Vitals. The 75th percentile means that 75% of recordings were lower than showcased Web Vitals values (e.g. 75% of page or site visitors had Largest Contentful Paint of 2.5s or less).
The overall values are categorised as good, to improve or poor. Below, with a breakdown of each metric performance, you can see the percentage of good and poor user experiences and determine where you should make improvements.
Why there is no data for my site?
Your site has to have enough traffic to be included in the CrUX report. New sites are added to the dataset every day, so keep checking in the future or try running a report on the entire domain. In the meantime, you can also monitor Core Web Vitals in Calibre!
How do Core Web Vitals impact SEO?
Google evaluates pages based on content, relevance, quality, engagement metrics and many other factors. Core Web Vitals are a page ranking signal for your pages. To give your site the best chance of ranking above your competitors, you should ensure that your Core Web Vitals fall within the recommended thresholds.
How can I improve Core Web Vitals?
There are numerous ways to improve Core Web Vitals. The best way is to continuously monitor site speed (with tools like Calibre) and follow actionable advice tailored to your context. If you don’t know where to start, read our Getting Started with Web Performance and The New Generation of Performance Metrics for Better User Experience guides!
Why does the assessment pass without First Input Delay?
First Input Delay is an optional metric in Core Web Vitals assessment. Lack of First Input Delay measurement means there is no user input for a given page visit. Without FID, your review is calculated based on the remaining Core Web Vitals: Largest Contentful Paint and Cumulative Layout Shift.
Why is First Contentful Paint, Time To First Byte and Interaction to Next Paint listed?
While these metrics are not Core Web Vitals, CrUX returns them as a diagnostic metrics that are also worth paying attention to. The Core Web Vitals set might be changed in the future to include some of them.
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