In the competitive landscape of digital performance, Core Web Vitals have emerged as critical metrics for evaluating a website’s user experience.
These metrics—Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS)—are essential components of Google’s page experience update. For site owners aiming to optimize their search engine rankings and deliver a great user experience, understanding and improving these metrics is non-negotiable.
This guide will break down Core Web Vitals, their significance, and actionable steps to improve your scores.
Whether you’re using tools like PageSpeed Insights, Google Search Console, or Chrome DevTools, this article will equip you with the knowledge to enhance your site’s performance.
What Are Core Web Vitals And Their Importance
Core Web Vitals are a set of performance metrics introduced by Google to measure the quality of a website’s user interaction and page load experience.
They focus on three key aspects:
- Loading Performance: Measured by Largest Contentful Paint (LCP).
- Interactivity: Measured by First Input Delay (FID).
- Visual Stability: Measured by Cumulative Layout Shift (CLS).
These metrics directly impact your site’s page speed, usability across different devices, and ultimately your position in search results. Websites that meet the thresholds for Core Web Vitals gain an advantage in Google’s ranking algorithm, making it a vital part of any SEO strategy.
Why Should You Care About Core Web Vitals?
Improving Core Web Vitals is not just about meeting Google’s standards; it’s about delivering a good user experience.
A poor score can lead to:
- Higher bounce rates due to slow load times or unstable layouts.
- Reduced engagement because of delayed responses to user input.
- Lower search rankings as Google prioritizes sites with better performance data.
For businesses, this translates into lost conversions and diminished trust. By addressing these metrics, you ensure your site provides a seamless experience for users across all kinds of devices.
Largest Contentful Paint (LCP)
What is LCP?
Largest Contentful Paint (LCP) is a metric that measures how long it takes for the largest visible content element on a web page, such as an image, video, or block of text, to fully load and become visible in the user’s viewport.
It is an important part of the Core Web Vitals because it reflects how quickly users can see the main content of your page, which directly impacts their first impression of your site.
How to Interpret Your LCP Score?
Google categorizes LCP scores as follows:
- Good: ≤ 2.5 seconds
- Needs Improvement: 2.5–4 seconds
- Poor: > 4 seconds
A good LCP score ensures that users can access your site’s primary content without unnecessary delays.
What Could Be Causing a Poor LCP Score?
Several factors can negatively impact your LCP score:
- Slow server response times (server response time).
- Render-blocking resources like JavaScript and CSS.
- Large images or videos without proper optimization.
- Lack of critical CSS or improperly defined size attributes for images.
Improving Your LCP Score
To enhance your LCP score:
- Optimize server response times by upgrading hosting or reducing time to first byte (first byte).
- Use lazy loading for non-critical images.
- Compress images and define proper size attributes.
- Minimize render-blocking resources through techniques like critical CSS extraction.
First Input Delay (FID)
What is FID?
First Input Delay (FID) measures the time it takes for a web page to respond when a user interacts with it for the first time. This interaction could be anything like clicking a button, tapping on a link, or typing into a form field.
A low FID score means that your website is responsive and provides a smooth user interaction, which is critical for a good user experience. High FID scores are often caused by heavy JavaScript code or tasks that block the browser’s main thread, delaying the response to user input.
How to Interpret Your FID Score?
Google’s benchmarks for FID are:
- Good: ≤ 100 ms
- Needs Improvement: 100–300 ms
- Poor: > 300 ms
A low FID score ensures users can interact with your site without frustrating delays.
What Could Be Causing a Poor FID Score?
Common causes include:
- Heavy JavaScript execution.
- Long tasks blocking the main thread.
- Inefficient third-party code.
Improving Your FID Score
To improve FID:
- Minimize unused JavaScript and reduce its execution time.
- Break up long tasks into smaller chunks.
- Use web workers for complex code execution.
Cumulative Layout Shift (CLS)
What is CLS?
Cumulative Layout Shift (CLS) measures how much the visible content on a web page unexpectedly shifts during loading. These shifts can occur when elements like images or ads load without predefined space or when fonts load late, causing text to move around. A high CLS score indicates poor visual stability, which can frustrate users and lead to a bad page experience.
For example, if a button moves just as someone tries to click it, this creates a negative impression. To achieve a low CLS score, it’s essential to define proper size attributes for images and videos, reserve space for dynamic content, and use efficient fonts.
How to Interpret Your CLS Score?
Google’s thresholds are:
- Good: ≤ 0.1
- Needs Improvement: 0.1–0.25
- Poor: > 0.25
A low CLS score ensures high visual stability, making your site more user-friendly.
Improving Your CLS Score
To reduce layout shifts:
- Reserve space for images using size attributes or CSS aspect ratio boxes.
- Avoid inserting content above existing content unless necessary.
- Use fonts that load efficiently to prevent shifts during rendering.
How to Measure Core Web Vitals?
Measuring Core Web Vitals is essential for understanding your website’s user experience and identifying areas for improvement.
You can use tools like PageSpeed Insights, Google Search Console, and Chrome DevTools to analyze key metrics such as Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). These tools provide both lab data (simulated tests) and field data (real-world user data from the Chrome User Experience Report).
For example, PageSpeed Insights offers a detailed breakdown of your site’s performance, including recommendations to improve metrics like site speed, visual stability, and response to user input. If you prefer real-time monitoring, tools like the Web Vitals Extension or custom scripts using the web-vitals.js library can also track these metrics directly in your browser.
Where Can I See My Website Core Web Vitals Report?
You can view your website’s Core Web Vitals report in tools like Google Search Console and PageSpeed Insights.
In Google Search Console, navigate to the “Core Web Vitals” tab under the “Experience” menu. This report groups URLs into categories like “Good,” “Needs Improvement,” or “Poor” based on their performance in metrics such as LCP, FID, and CLS.
It uses real-world data from the Chrome User Experience Report (CrUX) to give you insights into how users experience your site on both mobile and desktop devices.
Similarly, PageSpeed Insights provides both field data and lab data for individual pages, showing whether your site passes Google’s thresholds for a good user experience.
These reports highlight issues like slow load times or unstable layouts and offer actionable suggestions for improvement.
How Do I Know If My Website Passes The Core Web Vitals?
To check if your website passes the Core Web Vitals assessment, you need to ensure that all three metrics—LCP, FID, and CLS—meet Google’s thresholds. A “Good” score means LCP is ≤ 2.5 seconds, FID is ≤ 100 ms, and CLS is ≤ 0.1.
Tools like PageSpeed Insights or the Core Web Vitals report in Google Search Console will clearly indicate whether your site passes or fails.
The Search Console report groups URLs by performance status (“Good,” “Needs Improvement,” or “Poor”) and provides detailed insights into problematic areas such as high LCP times or excessive CLS values.
If your site meets these thresholds for at least 75% of user visits (based on CrUX data), it will pass Google’s Core Web Vitals assessment, improving your site’s rankings in search results and delivering a better overall page experience.
Improving Core Web Vitals Metrics
Upgrade Your Hosting
A slow server response time can negatively impact your Largest Contentful Paint (LCP) and overall site speed. Upgrading to a better hosting provider ensures faster delivery of your website’s content to users.
Look for hosting options with low latency and high reliability, as this will improve your page load time and enhance the user experience. Faster servers mean your site responds quicker, reducing delays in loading the main content.
Use a Content Delivery Network
A Content Delivery Network (CDN) helps distribute your website’s content across multiple servers worldwide, ensuring faster delivery to users based on their location. This reduces the time it takes for the largest content element to load and improves metrics like LCP score.
By using a CDN, you can also reduce server load and improve performance for users accessing your site from different regions, contributing to a better page experience.
Optimize Your Images
Large or unoptimized images can slow down your website and hurt your LCP score. Compressing images, using modern formats like WebP, and defining proper size attributes can significantly improve your site’s load time.
Optimized images not only enhance the visual stability of your page but also ensure that the largest contentful paint happens quickly, providing a smoother experience for users.
Use Page Caching
Page caching stores a static version of your web page, allowing it to load faster for returning visitors. This reduces the time needed to generate the page dynamically, improving both your site’s server response time and overall performance.
By implementing caching, you can enhance metrics like LCP and provide a faster, more reliable experience for users across all kinds of devices.
Reduce the Impact of Third-Party Code
Third-party code, such as ads or analytics scripts, can block important tasks and delay responses to user input, affecting metrics like First Input Delay (FID). Minimizing or deferring non-essential third-party scripts ensures that your site’s core functionality isn’t slowed down.
This optimization improves both interactivity and overall performance, contributing to better scores in tools like Google’s PageSpeed Insights and a more seamless browsing experience for users.
Tools to Measure Your Core Web Vitals
ContentKing
ContentKing is a powerful real-time monitoring tool that tracks your website’s performance, including Core Web Vitals like Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS).
It continuously audits your site, alerting you to issues such as poor page experience or changes in web vital metrics. With its user-friendly dashboard, you can view detailed insights and track performance trends over time.
The tool also integrates with platforms like Google Search Console, allowing you to manage multiple domains efficiently. ContentKing is especially helpful for identifying and prioritizing areas that need optimization to improve your site’s user experience and search rankings.
PageSpeed Insights (PSI)
PageSpeed Insights (PSI) is a free tool from Google that analyzes both lab data and real-world field data to assess your site’s performance. It focuses on key metrics like LCP, FID, and CLS to provide a comprehensive Core Web Vitals assessment.
The tool color-codes results as “Good,” “Needs Improvement,” or “Poor” and offers actionable suggestions to improve metrics like site speed, visual stability, and response to user input. PSI also displays data for mobile and desktop separately, helping site owners optimize their pages for different kinds of devices.
By addressing the recommendations in PSI reports, you can enhance your site’s overall performance and pass Google’s Core Web Vitals thresholds.
Google Search Console
Google Search Console (GSC) provides a dedicated report for monitoring your site’s Core Web Vitals, using real-world data from the Chrome User Experience Report (CrUX). It categorizes URLs as “Good,” “Needs Improvement,” or “Poor” based on their LCP, FID, and CLS scores.
The report highlights specific issues affecting your site’s performance, such as high LCP times or excessive CLS values, and groups affected URLs for easier prioritization.
GSC’s timeline feature allows you to track improvements over time, making it an invaluable tool for site owners aiming to enhance their site’s page experience and meet Google’s ranking requirements.
FAQ’s:
How Big of an SEO Impact Do Core Web Vitals Have?
Core Web Vitals have a significant impact on SEO as they are an official ranking factor in Google’s algorithm.
Metrics like Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS) directly affect your site’s page experience, which influences how Google ranks your site in search results.
While content quality and relevance remain important, passing the Core Web Vitals assessment gives your website a competitive edge by improving both user experience and search visibility.
Why Are Lab Data and Field Data Scores So Different?
The difference between lab data and field data lies in how they are collected. Lab data is generated in a controlled environment using tools like PageSpeed Insights, simulating ideal conditions such as fast internet and powerful devices.
On the other hand, field data comes from real users via the Chrome User Experience Report (CrUX), capturing performance across various network speeds and devices. This is why field data often reflects more variability and real-world challenges, while lab data is more consistent.
Why is There No Field Data For My URL Or Origin Summary?
If there’s no field data for your URL or origin summary, it likely means your site doesn’t have enough traffic to generate data in the Chrome User Experience Report (CrUX).
Field data relies on real-world user interactions, so low-traffic pages or new sites may not have sufficient performance data collected yet.
In such cases, you can rely on lab data from tools like Google’s PageSpeed Insights or Web.dev Measure to analyze and improve your site’s performance.
Do Non-Indexable Pages Impact My Core Web Vitals?
No, non-indexable pages do not directly impact your site’s overall Core Web Vitals assessment since they are not included in Google’s ranking calculations. Only indexable pages that appear in search results contribute to your site’s performance metrics in tools like the Search Console Core Web Vitals report.
However, optimizing all pages, even non-indexable ones, is still a good idea to ensure a consistently good user experience for visitors navigating throughout your site.
Conclusion
Improving your website’s Core Web Vitals—Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS)—is essential for delivering a great user experience and boosting your rankings in search results. These metrics directly impact how users perceive your site’s page speed, visual stability, and responsiveness to user input.
Tools like PageSpeed Insights, Google Search Console, and Chrome DevTools make it easier to measure and optimize these metrics.
Addressing issues like slow server response time, unoptimized images, and heavy JavaScript can help you pass the Core Web Vitals assessment and ensure your site performs well across all kinds of devices.
Remember, a fast, stable, and interactive website not only improves your SEO but also builds trust with users, keeping them engaged and satisfied. For site owners, focusing on Core Web Vitals is a smart strategy to enhance both performance and long-term success.