How To Fix Failed Core Web Vitals on a Website (Step-by-Step Guide)

Written by Arun Kumar

Quick Summary (Takeaway)

• Core Web Vitals = LCP + CLS + INP
• Fixing them improves user experience and rankings
• Focus on:
  • LCP (≤ 2.5s): Optimize images, server speed, loading priority
  • CLS (≤ 0.1): Fix layout shifts (images, fonts, ads)
  • INP (≤ 200ms): Optimize scripts, reduce delays
• Use both field data (real users) and lab data (tools like PageSpeed Insights) to diagnose issues

What Are Core Web Vitals?

Core Web Vitals are performance metrics that measure how real users experience your website.

Types of Data

1. Field Data

2. Field Data

Standard Metrics

1. How To Fix LCP (Largest Contentful Paint)

LCP measures how fast the main content (image/text) loads.

LCP Breakdown (2.5 Seconds)

LCP is divided into 4 parts:

How To Optimize LCP (Step-by-Step)

1. Time to First Byte (TTFB)

• Enable caching (page-level + server-level)
• Optimize database (remove junk, unused pages)
• Use CDN

2. Resource Load Delay

• Avoid lazy loading for above-the-fold content
• Use <img> tag instead of CSS/JS images
• Add priority tag for important images

3. Resource Load Duration

• Reduce image size (pixels & bytes)
• Convert formats:
  • ❌ PNG, JPG, BMP, TIFF
  • ✅ WebP, AVIF

4. Element Render Delay

• Keep website structure simple
• Avoid complex DOM

Fix LCP for Images

Fix LCP for Text

• Use system fonts (fast loading)
• Reduce font loading delays

2. How To Fix CLS (Cumulative Layout Shift)

LCP measures how fast the main content (image/text) loads.

How CLS Is Calculated

$CLS = IF \times DF$CLS=IF×DF

Where:

• IF (Impact Fraction) = Area affected
• DF (Distance Fraction) = Movement distance

Example:

• Total height = 1000
• Impacted area = 600 → 600/1000 = 0.6
• Movement = 500 → 500/1000 = 0.5

👉 CLS = 0.6 × 0.5 = 0.3

How To Fix CLS

1. Fix Image Dimensions

• Always define width & height

2. Handle Dynamic Content

• Set min-height for:
  • Dynamic sections
  • Lazy-loaded elements

3. Reserve Space for Ads

• Define fixed ad container size

4. Font Optimization

• Use system fonts like Arial
• Preload custom fonts using preload tag
• Avoid font swapping issues

CLS Optimization Table

3. How To Fix INP (Interaction to Next Paint)

INP measures how fast your site responds to user actions (click, tap, type).

INP Components

How To Fix INP

1. Reduce Input Delay

• Minimize background processes

2. Optimize Processing

• Reduce heavy scripts
• Keep JS files optimized

3. Improve Presentation

• Keep DOM simple
• Avoid complex UI rendering

Visual Summary (Core Web Vitals Fix)

FAQ’s

Conclusion

Fixing Core Web Vitals is about improving real user experience, not just scores.

• Optimize loading (LCP)
• Stabilize layout (CLS)
• Improve interaction speed (INP)

Follow the structured approach above to systematically fix issues instead of guessing.

If you want, we as an SEO Expert can audit your website’s Core Web Vitals and give you a personalized fix roadmap based on your real data (GSC + PageSpeed Insights).