We use Google's Web Vitals to provide unified guidance for quality signals that are essential to delivering a great user experience on the web.
Largest contentful paint
Provide a good loading performance.
LCP should occur within 2.5 seconds of when the page first starts loading.
Between 2.5 - 4 sec needs improvement. Over this is poor.
First input delay
To provide a good interactivity performance.
Pages should have a FID of 100 milliseconds or less.
Between 100ms - 300ms needs improvement.
Cumulative layout shift
Provide good visual stability.
Pages should maintain a CLS of 0.1. or less.
Between 100ms - 250ms needs improvement.