Picsum ID: 1031

Understanding Core Web Vitals: LCP, FID, CLS Explained with Real Data

Table of Contents
  1. What Are Core Web Vitals?
    1. LCP: Largest Contentful Paint
    2. FID: First Input Delay
    3. CLS: Cumulative Layout Shift

What Are Core Web Vitals?

Google Core Web Vitals are a set of metrics that measure user experience on the web. They became a ranking factor in 2021 and have only grown in importance since.

MetricFull NameGoodNeeds ImprovementPoor
LCPLargest Contentful Paint≤ 2.5s2.5s – 4.0s> 4.0s
FIDFirst Input Delay≤ 100ms100ms – 300ms> 300ms
CLSCumulative Layout Shift≤ 0.10.1 – 0.25> 0.25

LCP: Largest Contentful Paint

LCP measures the time it takes for the largest content element on your page to become visible. This is typically a hero image, a heading, or a video. Our benchmark: 0.8s on cached pages.

FID: First Input Delay

FID measures the time between a user interacting with your page and the browser being able to respond. With server-side rendering and minimal JavaScript, we achieve < 10ms FID.

CLS: Cumulative Layout Shift

CLS measures visual stability. By setting explicit dimensions on all images and reserving space for dynamic content, we maintain a CLS of 0.02 — well within the “good” threshold.

Core web vitals dashboard

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