How to Monitor Core Web Vitals Using Google PageSpeed Insights

Introduction

In today’s fast digital world, website speed and user experience matter more than ever. People expect websites to load quickly and run smoothly. If your site is slow or clunky, users will leave within seconds — and that means lost traffic, sales, or leads. On the other hand, a fast-loading, smooth website keeps visitors happy, improves engagement, and helps your website rank better on Google.

That’s where Core Web Vitals come in. These are special performance metrics that Google uses to measure the real-world user experience on your website. They focus on how fast your page loads, how quickly users can interact with it, and whether anything on the page shifts around unexpectedly. In short, Core Web Vitals help you understand how "usable" your site feels to people — not just to search engines.

But how do you check and improve these Core Web Vitals?

One of the easiest ways is through Google PageSpeed Insights (PSI) – a free tool from Google that helps you measure website speed and user experience.

In this article, we’ll explain:

• What Core Web Vitals are
• Why they matter for SEO and user experience
• How to use PageSpeed Insights to monitor them
• How to read the report and fix common issues

Let’s get started step by step in a simple and clear way.

What Are Core Web Vitals?

Core Web Vitals are a set of three important metrics created by Google. They measure how fast your website loads, how quickly it becomes usable, and how smooth the experience is for users.

Here are the three Core Web Vitals:

1. Largest Contentful Paint (LCP) – This checks how long it takes the biggest visible part of the page (like a banner image or large text block) to load.
• Good: Less than 2.5 seconds
• Needs improvement: Between 2.5 – 4.0 seconds
• Poor: More than 4.0 seconds
2. First Input Delay (FID) – This measures how fast your website responds when a user clicks, taps, or interacts with something for the first time.
• Good: Less than 100 milliseconds
• Needs improvement: Between 100 – 300 ms
• Poor: More than 300 ms
  
  
3. Cumulative Layout Shift (CLS) – This checks if the page layout shifts suddenly when loading (like buttons moving around or text jumping).
• Good: Less than 0.1
• Needs improvement: Between 0.1 – 0.25
• Poor: More than 0.25

These three metrics form the heart of user experience. If your site performs well on these, Google is more likely to rank it higher.

Why Core Web Vitals Matter

Let’s break down why these metrics are important:

• Better Rankings: Google uses Core Web Vitals as a ranking factor. A better score can help your site appear higher in search results.
• Improved User Experience: Fast and stable websites keep visitors happy. A slow or shaky site makes people leave.
• Higher Conversions: If your website is smooth, users are more likely to stay, explore, and buy or sign up.

Now that we know what Core Web Vitals are and why they’re important, let’s look at how we can check them using Google PageSpeed Insights.

Google PageSpeed Insights

Google PageSpeed Insights (PSI) is an online tool which is available without any cost by Google. It helps you check how fast your website loads and whether your Core Web Vitals are good or not.

It gives two types of data:

1. Field Data (Real-World Data): This comes from users who have actually visited your site using Chrome.
2. Lab Data (Simulated Test): This is a test run by Google’s servers to simulate a user visit and show potential issues.

With PSI, you get both real experience and simulated results to guide your improvements.

How to Use Google PageSpeed Insights (Step-by-Step)

Here’s a simple guide to using PageSpeed Insights:

Step 1: Visit the PageSpeed Insights Tool

Go to: https://pagespeed.web.dev

Step 2: Enter Your Website URL

Type or paste your website’s URL in the search box. You can enter:

• Homepage (e.g., https://example.com)
• Blog page (e.g., https://example.com/blog)
• Product page (e.g., https://example.com/product)

Click “Analyze” to run the test.

Step 3: Review the Results

After a few seconds, PSI will show you a report. It will include:

• A Performance Score (out of 100)
• Field Data from the Chrome User Experience Report
• Core Web Vitals Assessment
• Lab Data with scores for LCP, CLS, FID/INP, and more
• Opportunities and Diagnostics for improvements

Understanding the Report – What to Look For

Let’s break down the main parts of the PageSpeed Insights report.

1. Performance Score

This is a score between 0 and 100 that gives an overview of how fast your page is.

• 90–100: Excellent (Green)
• 50–89: Needs improvement (Orange)
• 0–49: Poor (Red)

This score is based mostly on Lab Data, not real user data.

2. Core Web Vitals Assessment

This section shows if your site passes the Core Web Vitals test. It uses Field Data from real users.

It shows status as:

• Passed – All Core Web Vitals are in the “Good” range
• Failed – One or more metrics are in “Needs improvement” or “Poor”

3. Field Data

This comes from real Chrome users. It shows actual experiences over the past 28 days for:

• LCP
• FID or INP (depending on availability)
• CLS

Look at the percentages and color bars. They help you see how many users had a good or bad experience.

4. Lab Data

This is simulated data generated from a test environment. It includes:

• LCP (Largest Contentful Paint)
• CLS (Cumulative Layout Shift)
• INP (Interaction to Next Paint, replacing FID)
• TTFB (Time to First Byte)
• FCP (First Contentful Paint)
• Speed Index
• Total Blocking Time (TBT)

Lab data helps you diagnose issues even if your site doesn’t have enough real-world data.

5. Opportunities

This section tells you what is slowing your site down and how much time you could save by fixing it.

Examples include:

• Reduce image size
• Eliminate unused CSS
• Avoid large layout shifts

Click each suggestion to see details.

6. Diagnostics

This part provides technical advice like:

• Too much JavaScript
• Long main-thread tasks
• Poor caching strategies

It helps developers improve the site's technical structure.

Fixing Core Web Vitals Issues (Common Tips)

Here’s how you can improve each Core Web Vital using insights from PageSpeed:

1. Fixing LCP (Speed Up Large Content Load)

• Optimize Images: Compress large images using tools like TinyPNG or WebP format.
• Lazy Load Below-the-Fold Images: Only load visible images first.
• Use a Fast Server: Choose reliable hosting and use CDNs (like Cloudflare).
• Minify CSS: Reduce file size of your stylesheets.
• Remove render-blocking resources: Load essential scripts early and defer the rest.

2. Fixing INP / FID (Improve Responsiveness)

• Minimize JavaScript Execution Time: Break long tasks into smaller chunks.
• Avoid Heavy Third-Party Scripts: Remove unnecessary trackers, ads, or widgets.
• Use Efficient Event Handlers: Optimize how your site handles clicks and inputs.
• Load JavaScript Asynchronously: Use async or defer attributes.

3. Fixing CLS (Avoid Layout Shifts)

• Set Width and Height for Images/Videos: Always define dimensions in HTML or CSS.
• Avoid Ads or Banners That Push Content: Keep them stable or load below main content.
• Preload Fonts: Use rel="preload" for custom fonts to avoid late font swapping.

Tracking Core Web Vitals Over Time

It’s not enough to check PSI once. You should monitor your website regularly.

Tools to Help You Track Progress:

1. Google Search Console
• Go to the “Core Web Vitals” report under “Experience”
• It shows performance for mobile and desktop versions
2. Chrome Extension: Lighthouse
• Run audits directly in your browser
3. Web Vitals Chrome Extension
• Shows real-time Core Web Vitals on any page
4. Google Analytics 4 (GA4)
• Track user behavior and match it with slow pages
5. CrUX Dashboard (Chrome UX Report)
• Built in Data Studio using real Chrome user data

Mobile vs Desktop – Why Both Matter

PageSpeed Insights gives separate results for Mobile and Desktop. Many websites score well on desktop but poorly on mobile.

Mobile optimization is crucial because:

• Most users browse on phones
• Mobile connections are slower
• Small screens highlight layout issues

Always check and optimize both versions of your site.

Helpful Practices to Improve PageSpeed and Web Vitals

Here are some practical things to do:

• Use a lightweight theme (if using WordPress)
• Limit plugins and use only essential ones
• Keep software updated (themes, plugins, CMS)
• Enable browser caching
• Use modern image formats (WebP, AVIF)
• Avoid autoplay videos above the fold
• Minimize redirects
• Host videos on platforms like YouTube instead of self-hosting

Final Thoughts

Core Web Vitals are not just a technical SEO thing—they’re directly linked to how people feel when they visit your website. A fast, stable, and interactive website helps you win both in search rankings and in user satisfaction.

Google PageSpeed Insights is one of the easiest tools to monitor these metrics. It gives you both real data and lab results to guide your fixes.

Whether you’re a blogger, small business owner, or web developer, regularly checking your site on PSI and taking action on its suggestions will lead to faster load times, better rankings, and more happy visitors. Improving Core Web Vitals isn’t a one-time task — it’s a habit that leads to long-term success.