How to Improve Core Web Vitals

The key to success for your WordPress website lies in the user experience. As a business owner, webmaster, or digital marketer, you should understand how to improve Core Web Vitals to enhance your website’s usability. Google’s Core Web Vitals provide essential metrics that empower you to measure and identify opportunities to optimize the performance of your website.

• What Are Core Web Vitals?
• How to Improve Core Web Vitals

What Are Web Vitals?

Web Vitals are the metrics displayed when you use the PageSpeed Insights tool. Web Vitals ensure that users enjoy a smooth and efficient experience. Google created this tool to offer detailed insights into website performance, enabling you to focus on areas that need improvement. Best of all, you don’t need to be a technical expert to use these tools – Google simplifies complex data into actionable steps that improve your website’s usability. By learning how to improve Core Web Vitals, site owners enhance performance across all devices and improve their site’s overall success.

What Are Core Web Vitals?

Core Web Vitals are specific metrics within Web Vitals that focus on the user experience, which will change over time. If you’re looking for how to improve Core Web Vitals, you should focus on understanding Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift. Google’s PageSpeed Insights tool currently emphasizes these three areas to grade your website’s user experience, but additional metrics are also important for overall performance.

Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) actively measures loading performance. It determines when the largest content element in the viewport becomes visible. This element could be a large image, video, or block of text. LCP helps you identify when the main content of the page has finished rendering on the screen and is visible to your user.

To ensure a good user experience, the largest contentful paint should occur within 2.5 seconds of when the page first begins loading. Common causes of a poor LCP score include slow server response times, render-blocking JavaScript or CSS, slow resource loading times, and client-side rendering.

Interaction to Next Paint (INP)

Interaction to Next Paint (INP) assesses how quickly a page responds to user interactions like clicks, taps, and key presses. INP measures the time between when a user starts an interaction and when the next frame is painted, offering insight into how responsive a site feels during use.

Good responsiveness fosters immediate visual feedback, indicating to users that the page responds to their actions. For instance, when users click an ‘Add to Cart’ button, a responsive site immediately shows that the item has been added, whereas poor responsiveness can confuse users and lead to multiple clicks.

A good INP score is 200 milliseconds or less. Scores between 200 and 500 milliseconds indicate room for improvement, while scores over 500 milliseconds suggest poor responsiveness. INP is the successor to First Input Delay (FID). FID only measured the first interaction. INP evaluates all interactions on a page, making it a more comprehensive metric for understanding overall user experience.

Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) actively tests your website’s visual stability. It measures the amount of movement a page experiences as elements shift because another element resizes or is added during loading. Layout shifts can frustrate and visually jar your visitors. Optimizing your website to minimize shifts can significantly reduce visitor frustration, encouraging them to remain on your webpage.

To provide a good user experience, your web pages should have a score that is less than 0.1. The most common causes of a poor CLS score are images, ads, embeds, or iframes without dimensions, dynamically injected content, Web Fonts causing FOIT/FOUT, and actions waiting for a network response before updating the DOM.

Other Key Web Vitals Metrics

While the three Core Web Vitals – LCP, INP, and CLS – are the most emphasized metrics, the Google PageSpeed Insights tool uses several other metrics to evaluate website performance. Understanding how to improve Core Web Vitals often means looking at the broader range of user experience signals.

Time to First Byte (TTFB)

TTFB, or Time to First Byte, measures the amount of time it takes for a user’s browser to receive the first byte of data from your web server after making an HTTP request. While TTFB isn’t one of the official Core Web Vitals, it can significantly impact your Largest Contentful Paint (LCP) score. A faster TTFB means that your server is responding quickly, leading to a better user experience.

A high TTFB often signals underlying issues. Factors that impact the score include server performance and resources, hosting configurations, and the number of redirects. To improve TTFB, optimize your server resources and backend processes, upgrade your hosting environment, and reduce redirects when possible.

Total Blocking Time (TBT)

Total Blocking Time (TBT) actively measures how long it takes for the site to respond to user actions such as clicks, taps, or scrolling. This metric is vital because it indicates how responsive a page feels during loading. A low TBT score signifies that the page loads quickly, keeping users engaged and less likely to leave the site.

A high TBT score often indicates that large or unoptimized JavaScript slows down the browser’s ability to respond to user actions. This condition increases TBT while affecting other performance metrics like Interaction to Next Paint (INP). To improve TBT, fix inefficient JavaScript and optimize resource loading; this action helps make important parts of your site interactive more quickly.

First Contentful Paint (FCP)

First Contentful Paint (FCP) measures how quickly the first piece of content—like text or images—appears on the screen. It generally shapes the user’s first impression of your website. A fast FCP reassures visitors that the page is loading, which reduces frustration and bounce rates.

Improving FCP can also help reduce Largest Contentful Paint (LCP) times, indicating that your site’s resources load efficiently. To optimize FCP, focus on strategies such as compressing CSS, deferring non-essential JavaScript, and using lazy loading for images. Thus, leveraging a Content Delivery Network (CDN) helps reduce load times by serving content from servers closer to users.

How to Improve Core Web Vitals

If you’re wondering how to improve Core Web Vitals for your website, start with Google’s PageSpeed Insights. This tool analyzes your site and provides both lab and field data. Lab data is useful for identifying technical performance issues in a controlled environment, while field data reflects real-world user experiences. Going over everything shown in the report can require effort, but it’s worth the time. Higher PageSpeed scores lead to better SEO rankings and happier end users.

If you’re running a WordPress website, using the W3 Total Cache plugin offers an excellent way to improve Core Web Vitals. This WordPress caching plugin optimizes both speed and user experience, leading to a higher PageSpeed score.

Keep in mind that every website will have different diagnostic results and the scores can vary a bit with each run. Below are some of the most important diagnostics and how to improve Core Web Vitals.

Eliminate Render-Blocking Resources

Render-blocking resources, such as CSS and JavaScript, delay your page’s loading because the browser must download and process these resources before rendering content. This condition slows overall page load time, particularly affecting First Contentful Paint (FCP) and Largest Contentful Paint (LCP).

How to Improve:

• Eliminate Render-Blocking CSS.
• Minimize the use of blocking CSS and JavaScript by deferring non-essential files.
• Use asynchronous loading (async or defer attributes) for JavaScript.
• Inline critical CSS to load only what’s necessary for above-the-fold content.

Reduce Unused JavaScript and CSS

Loading unnecessary JavaScript and CSS files wastes resources and increases page load times. These files require time to download, parse, and execute, which can negatively affect Total Blocking Time (TBT) and Interaction to Next Paint (INP).

How to Improve:

• Defer or remove unused CSS and JavaScript from your pages.
• Use tools like Chrome DevTools to identify which scripts and styles aren’t being used.
• Split code into smaller bundles and load only the code needed for the specific page.

Largest Contentful Paint (LCP) Element

LCP measures how long the largest visible element (such as an image, video, or large block of text) takes to load. If the LCP element loads slowly, it negatively impacts user experience.

How to Improve:

• Optimize the size and format of the LCP element (such as compressing images).
• Use a Content Delivery Network (CDN) to serve content more quickly.
• Minimize render-blocking resources to speed up the loading of the LCP element.

Serve Images in Next-Gen Formats

Next-gen image formats, such as WebP or AVIF, provide better compression and quality than traditional formats (JPEG, PNG). Serving images in these formats reduces file size, enhances loading times, and lowers LCP.

How to Improve:

• Convert your images to WebP or AVIF formats.
• Use lazy loading for off-screen images to improve load times for above-the-fold content.
• Set up fallback formats for browsers that don’t support these next-gen formats.

Properly Size Images

Improperly sized images consume more bandwidth than necessary, leading to slower page loads. Large, non-optimized images increase LCP times and overall page weight.

How to Improve:

• Resize images to fit the dimensions they will be displayed at on the screen.
• Use responsive image techniques to serve different image sizes based on the user’s device.
• Compress images without losing quality to reduce file size.

Minimize Main-Thread Work

The main thread processes most tasks on your site, including rendering and handling user interactions. When overloaded with heavy tasks like parsing JavaScript, this condition leads to a poor user experience by blocking the page’s responsiveness.

How to Improve:

• Reduce the size and complexity of JavaScript files.
• Break up long-running tasks to prevent blocking the main thread for extended periods.
• Optimize how resources (like CSS and JavaScript) are delivered and used on your website.

Reduce the Impact of Third-Party Code

Third-party scripts (such as analytics, ads, or social media embeds) can slow down your page’s performance by consuming resources and blocking rendering.

How to Improve:

• Load third-party scripts asynchronously or defer them until after the page has loaded.
• Limit the number of third-party scripts on your site, keeping only those essential for your business goals.
• Monitor and optimize the performance of third-party resources using browser developer tools.

PageSpeed Tests

Curious about the potential impact of these techniques? We researched it! Explore our PageSpeed Test series to discover how each feature contributes to improving PageSpeed scores.

Conclusion

Understanding how to improve Core Web Vitals is essential for both search engine rankings and user satisfaction. As web technologies and user expectations evolve, focusing on these critical metrics ensures that your website remains competitive. By optimizing loading speed, interactivity, and visual stability, you enhance both user experience and search performance.