Core Web Vitals: How To Measure And Improve Your Site’s UX

Learn how to boost your UX and SEO with Core Web Vitals, plus tips and tools to optimize for loading, interactivity, and visual stability.

Ever clicked on a website, only to wait and wait and then give up? Or you’ve tried to tap a button, and nothing happens for what feels like ages. Annoying, right? Understanding Core Web Vitals helps you create a smoother experience, making visitors feel appreciated and encouraging them to stay longer. These three key performance metrics—how quickly your site loads, how interactive it is, and how stable the page looks while loading—are essential for a user-friendly website. Improving these can boost your site’s UX and rankings, showing you care about your visitors’ experience.

What Are Core Web Vitals, and Why Do They Matter?

Introduced in 2020, Core Web Vitals focus on three user experience aspects:

1. Loading Speed (Largest Contentful Paint – LCP): Measures loading speed, which checks how long the main content of a page takes to load. A good LCP is under 2.5 seconds. LCP directly affects how quickly a user sees a page load. To Optimize. To improve LCP, optimize images, use a fast hosting provider, and reduce unnecessary scripts.
2. Interactivity (First Input Delay – FID): It shows how quickly a page responds when a user clicks a button or a link. That’s what this measures. A good response time is under 100 milliseconds. For better FID, minimize JavaScript, remove unused code, and use browser caching.
3. Visual stability (Cumulative Layout Shift – CLS): Measures visual stability. It checks if elements move around while the page is loading. A good CLS score is less than 0.1. To fix CLS, avoid sudden ads or pop-ups, and use proper font loading.

How to measure Core Web Vitals: Tools and techniques

Measuring Core Web Vitals is essential for understanding how your website performs in terms of user experience. Fortunately, there are tools to help you assess and improve your scores. Google mainly focuses on three Core Web Vitals: Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS).

Here are some of the most valuable tools and how to interpret the data:

Google PageSpeed Insights: The first and most popular tool. You need to enter your website URL, and it shows Core Web Vitals data for both mobile and desktop. It provides field data (user data) and lab data, along with suggestions to improve performance.

Google Search Console: is a free, supportive tool that offers valuable insights into your website’s performance in Google Search results. It’s dedicated Core Web Vitals report groups pages into good, needs improvement, or poor, helping you feel reassured and capable of addressing issues effectively. Using these tools can make you feel more in control of your website’s performance and your ability to enhance user experience.

Common Mistakes To Avoid When Improving Core Web Vitals

Core Web Vitals are essential metrics that measure how fast, stable, and user-friendly a website is. These include Largest Contentful Paint (LCP) for loading speed, Interaction to Next Paint (INP) for interactivity, and Cumulative Layout Shift (CLS) for visual stability. While many website owners try to improve these metrics, they often make common mistakes that can slow down progress or even harm performance. Avoiding these mistakes can help you achieve better results.

When working to enhance Core Web Vitals, it’s easy to fall into some common traps. Here are five common ones to avoid:

1. Focusing too much on one metric: It’s tempting to put all your effort into improving just one metric, especially if it’s performing poorly. But this approach can be counterproductive.

Core Web Vitals work together to provide a comprehensive picture of your site’s user experience. Neglecting one area while improving another might not lead to the overall improvement you’re aiming for. Ignoring metrics such as INP or CLS can lead to frustrated users and higher bounce rates. For best results, always aim for a balanced improvement across all Core Web Vitals metrics.

 2. Overlooking real user data: One common mistake when improving Core Web Vitals is overlooking real user data. Many website owners rely solely on lab tools like PageSpeed Insights or Lighthouse, which measure performance in controlled environments. However, real users may experience different loading times due to device type, network speed, and location. Ignoring real user data can lead to incorrect conclusions and wasted optimization efforts. To get accurate insights, website owners should regularly check Google Search Console and Chrome User Experience Report. These tools show how actual visitors experience the website and help prioritize the right performance improvements. Don’t rely solely on lab data. Consider field data from real users when optimizing your Core Web Vitals.

3. Neglecting mobile performance: Neglecting mobile performance is a common mistake when improving Core Web Vitals. Since most users browse websites on mobile devices, a slow or poorly optimized mobile site results in a poor user experience. Heavy images, large fonts, unoptimized JavaScript, and complex layouts can slow down loading speed and delay interactions on mobile. Google uses mobile-first indexing to assess your site for ranking, so it’s wise to prioritize your site’s mobile experience. Don’t just look at desktop performance.

Mobile devices often have less processing power than desktops and may be on slower networks, making performance optimization even more critical.

4. Not regularly monitoring performance: Improving Core Web Vitals isn’t a one-time thing. Your site’s performance can degrade over time as layouts and content change.

Schedule regular monitoring of your Core Web Vitals – such as with Semrush’s Site Audit tool – to catch and address issues early.

5. Ignoring cumulative impacts: Sometimes, small changes that seem insignificant on their own can, together, have a significant impact on your Core Web Vitals. Many website owners fix one issue at a time without checking how multiple changes affect overall performance. For example, adding new scripts, images, or design elements may seem small, but together they can slow down page load and reduce interactivity. It’s essential to review full-page performance after every update. Always test how changes work together to ensure they improve, not harm, the overall user experience.