What are the Core Web Vitals?
Core Web Vitals, are three metrics that score a user's experience loading a webpage.
Google specifies three Core Web Vitals
- Largest Contentful Paint (LCP)
- First Input Delay (FID)
- Cumulative Layout Shift (CLS)
These metrics show how your pages perform, based on real world usage data. Core Web Vitals are a subset of factors that will be part of Google’s “page experience” score.
Core Web Vitals metrics show:
- how quickly page content loads.
- how quickly after a browser loaded a webpage can respond to a user's input.
- how unstable the content (shifting items) is as the browser is loading the web page.
Metric | Good | Needs improvement | Poor
- LCP | <=2.5s | <=4s | >4s
- FID | <=100ms | <=300ms | >300ms
- CLS | <=0.1 | <=0.25 | >0.25