Core Web Vitals

What are core web vitals?

Metrics that measure the user experience of a website

Core web vitals are a group of metrics used to evaluate the quality of a website — specifically its user experience (UX). While it is difficult to measure user experience due to its subjective nature, core web vitals provide quantifiable and practical UX metrics for web developers.

Google introduced core web vitals in 2020 as a subset of its broader group of standards known as “web vitals.” Core web vitals are considered to be the most essential measurements that apply to all websites. The initial 3 core web vitals include:

  1. LCP (Largest Contentful Paint) — the speed at which a webpage loads
  2. FID (First Input Delay) — the time before a user interacts with a page
  3. CLS (Cumulative Layout Shift) — the stability of the visual elements on a page

Not only are core web vitals helpful when crafting a high-quality user experience, the metrics also serve as an important SEO measurement. Google has stated that it plans to take core web vital scores into consideration when determining page ranking.


My team plans to improve our website’s user experience by closely monitoring its core web vitals
Example core web vital scores from Google
Example core web vital scores from Google

Related Slang


Updated June 11, 2021

Core Web Vitals definition by

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