Glossary
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Core Web Vitals

Core Web Vitals

Core Web Vitals (CWV) are metrics determined by Google that, together with other metrics, represent the page experience of a website. They are essential to describe the user-friendliness of a website and consist of three parameters:

  • The Largest Contentful Paint (LCP) describes how long the largest element visible without scrolling takes to load completely.
  • The Cumulative Layout Shift (CLS) describes how stable the layout is during loading (for example, whether visible elements shift).
  • Der First Input Delay (FID) beschreibt, wie viel Zeit zwischen der ersten Aktion eines Users auf einer Website und der Reaktion des Browsers vergeht.

Importance of Core Web Vitals for SEO

Even the best content cannot keep users on a poorly usable website with long loading times. For this reason, Google rankings have long been based not only on the content of a website, but also on its user-friendliness. The values that are currently best suited for this purpose have been combined by Google into the Core Web Vitals.

Since June 2021, the Core Web Vitals are considered an official ranking factor by Google. A few months after publication, Sistrix proved with a study that websites with good CWV generally perform better than those with poor values.

Best Practices: How Website Operators Can Leverage Core Web Vitals

The Core Web Vitals can be determined via the Google PageSpeed Insights application or via Search Console. In addition, website operators can use the Lighthouse Audit or the CrUX API. For the optimization of CWV applies:

  • Good LCP values are under 2.5 seconds. They can be achieved by compressed image and text files and preloading important resources.
  • Good CLS values are less than 0.1, and can be achieved by giving image and video files fixed size attributes. Alternatively, space is reserved using CSS aspect ratio fields.
  • Good FID values are a maximum of 100 milliseconds. To achieve them, JavaScript is reduced or disabled and the source code is streamlined. Irrelevant third-party scripts can be removed. Instead, a browser cache should be present.

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