Website performance metrics for overall good user experience. In Core web vital Update performance of any web page measured by four factor.

  1. First Contentful Paint (FCP)
  2. First Input Delay (FID)
  3. Largest Contentful Paint (LCP)
  4. Cumulative Layout Shift (CLS)

In core web vital there are performance score and metric values. Your website page have to passed the Core Web Vitals assessment. Page passes the Core Web Vitals assessment to know use the Lighthouse Scoring Calculator and improve the metric values.

Core web vital google seo update is based on user-centric performance metrics. Reference:

What is performance of a website? what factors are under performance of a website? Accurately measure how users experience the performance of a web page.

How Core web vital metrics are measured?

Performance metrics are generally measured in one of two ways:

In the lab: Using tools to simulate a page load in a consistent, controlled environment. Before measure performance of webpage on real users, so testing them in the lab before the feature is released is the best way to prevent performance regressions.

In the field: on real users actually loading and interacting with the page.

Types of core web vital metrics?

There are several other types of metrics that useful to know how users perceive performance? Perceived load speed: how quickly a page can load and render all of its visual elements to the screen.

Load responsiveness: how quickly a page can load and execute any required JavaScript code in order for components to respond quickly to user interaction
Runtime responsiveness: after page load, how quickly can the page respond to user interaction.

Visual stability: do elements on the page shift in ways that users don’t expect and potentially interfere with their interactions?

Smoothness: do transitions and animations render at a consistent frame rate and flow fluidly from one state to the next?

All above given performance metrics. no single metric is sufficient to capture all the performance characteristics of a page.