Core Web Vitals
                     LET’S KNOW 
ABOUT CORE 
WEB VITALS
Presented by Chandra Mukhi
WHAT ARE CORE WEB VITALS?
Core Web Vitals are a set of performance 
metrics defined by Google to measure user 
experience on a webpage.
They focus on three key aspects: loading 
performance, interactivity, and visual stability. 
 These metrics are essential for SEO and 
overall website usability.
THE THREE CORE WEB VITALS:
LCP : Largest Contentful 
paint
FID :  First Input Delay
CLS : Cumulative Layout 
Shift
WHAT IS LCP 
Largest Contentful Paint (LCP) – Loading 
LargesPte Crofonrtmenatnfucle Paint (LCP) measures how long it takes for 
the largest visible element to load on a webpage. (Elements 
like image, text block, or video)
•                                                           2.5sec                                     4sec
• LCP Scoring
• Good: ≤ 2.5 seconds
• Needs Improvement: 2.5 – 4.0 seconds
• Poor: > 4.0 seconds
what is 
FID (First Input Delay)-
FID (First Input Delay) meaIsnurteesF rhoaIwDc qtuii cvkilyt ya webpage responds to a user's 
first interaction
A low FID means the site feels fast and responsive. If FID is high, users 
experience lag or delays when trying to interact with the page.
100ms                          
FID Scoring (Google’s 300ms
Standards)
• Good: ≤ 100 ms
• Needs Improvement: 100 – 300 
ms
• Poor: > 300 ms
What is 
CLS (Cumulative Layout Shift) -stability
Measures how much visible conteCnt mLovSes unexpectedly while a page loads. 
A high CLS means elements jump around, leading to a bad user experience.
• CLS Prevents frustrating user experiences, like clicking the wrong button 
due to a sudden layout shift.
• Google uses CLS as a ranking factor in search results (SEO impact).
0.1                              0.25
CLS Scoring (Google’s 
Standards)
• Good: ≤ 0.1
• Needs Improvement: 0.1 – 0.25
• Poor: > 0.25
What Causes High 
A high CLS score means your webpage elements are shifting too much. Common 
CLS?causes include:
• Images Without Defined Dimensions
• Ads, Banners, or Embeds Loading Late
• Dynamically Injected Content
• Web Fonts Causing FOUT/FOIT
• Slow Loading Elements
`
. WHY LCP ,FID, BECOME SLOW?
• Slow Server Response Times
• Render-Blocking Resources
• Large Images or Videos
• Slow Client-Side Rendering (JavaScript Issues)
• Too Many Third-Party Resources
•  Poor Browser Caching Strategy
• High Initial Server Load (TTFB Delay)
HOW TO IMPROVE LCP,FID, CLS
• Optimize Images & Videos
• Improve Server Response Time
• Minimize Render-Blocking Resources
• Enable Browser Caching
• Reduce JavaScript Execution Time
Tools to Measure & Fix LCD, FID, CLS 
• Google PageSpeed 
Insightst
• Google Search Console
• Chrome DevTools
• Lighthouse 
THANK YOU