Pay Attention to Web Performance Metrics to Improve the UX

May 8, 2023

Advances in technology and increases in the numbers of online users have made business owners aware of the importance of providing a seamless user experience for their customers.

One crucial aspect of such an online user experience is Web performance, which can have a significant impact on user engagement and conversion rates. Thus, in the world of UX design, it is important to pay attention to Web performance metrics. They provide a crucial indicator that helps you to ensure that users

  • engage with a Web site
  • stay on a Web site for longer periods of time
  • convert into new customers

In this article, I’ll explore the importance of Web-site performance metrics in UX design and describe how you can use them to improve the overall user experience of a Web site.

Champion Advertisement
Continue Reading…

What Is User Experience?

User experience describes how users feel about their interactions with a product or service and encompasses all aspects of the user’s experience, including the following:

  • emotions
  • attitudes
  • perceptions
  • behaviors, or how users interact with a product or service

This is why businesses should strive to create digital products or services that provide a seamless and engaging experience for users by doing the following:

  • understanding the needs and goals of the target audience
  • conducting user research and usability testing
  • creating prototypes and wireframes
  • designing the product or service to meet the needs and expectations of users

A personalized approach to creating products and services leads to

What Is the Role of Web Performance Metrics in UX?

First, let’s briefly discuss what I mean by Web performance metrics, which refer to a set of quantifiable measurements that you can use to evaluate and analyze the following aspects of a Web site:

  • speed
  • responsiveness
  • efficiency

These metrics can help you to assess a Web site’s performance by

  • providing insights into the user experience
  • identifying potential issues that could lead to a poor user experience
  • monitoring the Web site’s overall health

Now, let’s consider the following common Web performance metrics:

  • Page Load Time—This metric measures the time it takes for a Web page to fully load in a user’s browser. For example, it might take 3.5 seconds to load the home page of a Web site. Ideally, a Web page’s load time should be under 2.5 seconds.
  • Time to First Byte (TTFB)—This metric indicates the time it takes for a Web server to respond to a user’s request. For example, it might take 300 milliseconds to receive the first byte after requesting a Web page. Ideally, a Web page’s Time to First Byte should be under 200 milliseconds. However, this metric is also content dependent—for example, it should take less than 100 milliseconds for static content, but between 200 to 500 milliseconds for dynamic content to load.
  • Speed Index—This is the average time it takes to display the visible part of a Web page to the user. For example, it could take 2000 milliseconds for the visible portion of a Web page to appear. Ideally, a Web site’s speed index should be under 4.3 seconds.
  • Time to Interactive (TTI)—This metric measures the time it takes for a Web page to become interactive—that is, the amount of time following which the user can interact with the elements on a Web page—such as buttons and links. For example, it might take 5 seconds for a page to become interactive after it has fully loaded. Ideally, a Web page’s TTI should be under 3.8 seconds.
  • Number of Requests—This is the total number of HTTP requests a browser makes to load a Web page, including requests for images, scripts, and other resources. For example, it might take 30 requests to load a Web page. Ideally, loading a Web page should not require more than 50 HTTP requests.
  • Conversion Rate—This calculates the proportion of users who finish a planned activity such as paying for something or completing a form. For example, a 3% conversion rate for a Web page means that just three out of every 100 visitors completed the desired action. Ideally, a Web page should have a conversion rate of between 2% to 5%, although this can vary depending the industry or business domain.

Why Are Web Performance Metrics Important for UX?

Web-site performance metrics play several crucial roles in improving the user experience.

Identifying Areas for Improvement

Performance metrics such as the following can help you to identify pages on a Web site that are slow or causing delays:

  • Page Load Time
  • Time to First Byte (TTFB)
  • Total Page Size

Prioritizing Optimizations

Performance metrics can help you to prioritize optimizations depending on their impact on the user experience. For example, optimizing large images or reducing the number of HTTP requests can have a more significant impact on performance than minifying code or using a content delivery network (CDN).

Monitoring the Impacts of Changes

Web site owners and developers can see how changes to a site impact its speed and performance with the help of the following types of monitoring tools:

Aiding A/B Testing

You can use performance metrics in A/B testing—as well as other forms of usability testing—to evaluate the impact of different design and optimization strategies on the user experience. Thus, you can validate hypotheses and determine the best course of action for improving a product’s user experience.

Key Web Performance Metrics to Consider for UX

To improve a Web site’s user experience, consider the following key Web performance metrics:

  • Largest Contentful Paint (LCP)—LCP is part of Google’s Core Web Vitals, a set of metrics for measuring key aspects of Web performance and user experience. The LCP is considered a crucial metric because it reflects how quickly a user can start interacting with a page’s content, which is essential for a good user experience.
  • First Input Delay (FID)—This Web performance metric measures the time it takes to process a user’s first interaction with a Web page. Thus, it measures the delay between the user’s input and the Web site’s response, which is important for the user experience.
  • Cumulative Layout Shift (CLS)—This metric measures the visual stability of a Web page as it loads. Specifically, it indicates how many unexpected layout shifts occur during the loading process.
  • Time to First Byte (TTFB)—This metric measures the amount of time it takes for a browser to receive the first byte of the response from a server after making a request. In other words, it measures the time between the user’s request and the server’s initial response.
  • Total Blocking Time (TBT)—This metric measures the amount of time a Web page cannot respond to user input during its loading and rendering process. In other words, TBT measures the time during which the page is unresponsive to user interactions because of time-consuming loading and rendering tasks.

Many Web sites deliver optimal Web performance metrics for the user experience, including the following examples:

  • Google
  • Amazon
  • LinkedIn
  • Airbnb

Tools for Measuring Web Performance Metrics

There are several tools available for measuring Web-site performance metrics. Some of the most popular tools include the following:

  • Google PageSpeed Insights—This tool measures both desktop and mobile performance and provides suggestions for improving performance.
  • WebPageTest—This tool provides detailed performance metrics, including a filmstrip view of the page-loading process.
  • GTmetrix—This tool tracks a range of performance metrics, including PageSpeed and YSlow scores, along with suggestions for improving them.
  • Pingdom—This tool offers a range of performance metrics, including load time, page size, and the number of requests.
  • Lighthouse—This open-source tool from Google measures performance and provides suggestions for improvement, as well as accessibility and search-engine optimization (SEO).

Best Practices for Improving Web Performance Metrics for UX

Improving Web performance metrics is crucial to enhancing the user experience of a Web site. Let’s look at some best practices for improving Web performance metrics:

  • optimizing images—Compress images to reduce their file size and use the appropriate image formats—for example, JPG for photographs and PNG for graphics. This reduces the time it takes for the images on a Web page to load.
  • minimizing HTTP requests—Reduce the number of HTTP requests by combining CSS and JavaScript files and using CSS sprites. Doing so reduces the load time of a Web page.
  • enabling browser caching—By using browser caching to store frequently used resources on the user’s device, you can reduce the number of requests to your server and improve load times.
  • using a Content Delivery Network (CDN)—A CDN can store your Web site’s resources in multiple locations, bringing them closer to the user. This reduces the latency of requests and improves load times.
  • reducing server response time—Optimize your server response time by using a fast server, reducing the number of database queries, and optimizing your code. This improves load times and the user experience.

By implementing these best practices, you can significantly improve your site’s Web performance metrics and enhance the overall user experience on your Web site.


Paying attention to Web-site performance metrics such as Time to First Byte (TTFB) and Total Blocking Time (TBT) is essential for business owners and others who are passionate about the user experience. This can enable a business to improve their customers’ user experience and drive their engagement with their Web site, ultimately lead to increased conversions and revenues.

To maximize the positive impacts of monitoring Web-site performance metrics, business owners should also do the following:

  • Hire good UX writers and designers.
  • Monitor all these metrics regularly.
  • Make adjustments as necessary to continue delivering a superior user experience. 

Senior Digital Marketing Executive at Middleware and The Next Scoop

Ahmedabad, Gujarat, India

Srushti VachhrajaniSrushti is an ambitious, passionate, out-of-the box thinker who has vast exposure in digital marketing. Her key focus is serving her clients with the latest innovations in her field, leading to fast, effective results. Working beyond expectations and delivering the best possible results is her professional motto. In addition to her work, she loves travelling, exploring new things, and spending quality time with her family.  Read More

Other Articles on Metrics

New on UXmatters