Website page speed is the time it takes from a user clicking a link to the complete display of all content on the web page. During this period, the browser receives the first packet of information, technically termed as the “first byte from the server”. This metric is measured in seconds or milliseconds separately for desktop and mobile devices. In this article, we will explain in detail how to analyze website speed, what to pay attention to, and which tools to use.

Page speed and site speed are two different metrics. The first one refers to a specific page, while the second represents the average value for several selected pages on the website.

What is being discussed?

Why is website speed analysis needed?

Imagine this: you arrive at a restaurant to have dinner after a hard day’s work, but you’re forced to wait 5 minutes for the waiter. Another 10 minutes pass after your order is taken, but all the tables are served except yours. After another 20 minutes of waiting, you no longer notice the taste of the dish, its aroma, or sophistication. You feel that the dinner is not worth the money you paid for it. Without leaving a tip, you finish what’s on your plate and head home, never returning to that establishment again.

Similar situations occur on the internet. Users want to consume information quickly. According to numerous studies, people leave a website and seek an alternative if the web resource takes longer than 3 seconds to load.

Average download speed

Unfortunately, a significant number of online stores and other types of websites experience loading issues on desktop due to a large amount of content, interactive elements, and technical deficiencies. The situation is even worse for mobile devices. More than 70% of users who spend time online using smartphones and tablets encounter slow or incomplete loading issues. It is known that the conversion rate on mobile devices is lower than on desktops, despite mobile devices accounting for over 50% of total web traffic.

“Remember that mobile pages are considered separately for SEO results. The mobile pages of your site do not automatically inherit the SEO rating of the main site. For users searching on mobile devices, the page rating is calculated separately based on the speed of the mobile page, not based on the speed of the main site page. This means that website owners should pay as much attention (if not more) to the speed of the mobile version of the site”. The Importance Of Page Speed Optimization, — Chuck Kim, former Forbes Councils Member

Website speed analysis can reveal reasons for decreased sales that you may not have been aware of, and it can help solve a range of issues.

  • High bounce rate: According to Google statistics, this figure increases by 32% if the page load time is 3 seconds or more.
  • Low page depth: If large files load too slowly or incorrectly, or if the site freezes on a smartphone, users will stop interacting with the website.
  • Low search engine ranking: Website speed directly affects SEO.
  • Decreased conversion: Poor SEO and low traffic negatively impact sales. According to one study, Walmart reported that with every second of increased page speed, its conversion rate increases by 2%.
  • Negative impact on brand reputation: Users will not bookmark a slow site and certainly will not recommend it to friends. People associate the level of a company and the quality of its products not only with the website design and content but also with its usability.

If you make it a habit to regularly check your website speed, addressing the aforementioned issues will be quite straightforward. To start, you should analyze the key indicators of your site’s speed, after which you can delegate optimization to a specialist.

Indicators of website or webpage speed

The loading speed of a webpage depends on a combination of factors. Let’s look at the main web indicators that affect website promotion and conversion. You can identify them through a free and quick online analysis of website speed.

  1. Largest Contentful Paint (LCP). This metric pertains to the loading time of a webpage, specifically indicating when the main content of the page has loaded adequately.
  2. First Input Delay (FID). This refers to the time from when a user first interacts with a site to when the browser is able to respond to that interaction. It determines the interactivity of the page.
  3. Cumulative Layout Shift (CLS). This metric reflects the visual stability of a page. If the layout shifts, users may accidentally click on the wrong button on the page, causing frustration and prompting them to leave the site.

The key web metrics are interconnected with each other and with other parameters such as mobile responsiveness, secure browsing, HTTPS, and so on.

search signals for page experience

To view this infographic in full size, please download PDF Search signals for page experience

Other important metrics include page load time, first contentful paint, number of server requests, page size, and more. You can assess each of these and get optimization recommendations using one of the website speed testing services.

Tools for Checking Website Speed

In this article, we will examine popular website speed analysis services. To demonstrate the capabilities of each of them, we will analyze the website Rozetka.

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One of the main features of the tool is its ability to perform multiple tests — up to 9 analysis runs. You can analyze only the first visit or enable repeat viewing, where the service page speed, closes the browser, and then reloads the site again. After this, the user receives results of the page speed optimization check, cascade diagrams for each run, and suggestions for improvement.

In the free version, you have access to selecting testing parameters such as the device used to access the page, connection type, browser, and region. The paid version costs $180 per year and includes additional features such as increased number of regions, priority tests, access to API, integrations, private tests, bulk testing, experiments, and specialized support.

The first part of the analysis results includes the summary of the performance, namely speed, quality of layout, and security of the connection.

Fast? Not bad… This site connected quickly and delivered the initial code promptly. It started displaying content very swiftly. There were no requests blocking rendering.

Is it usable? Looks great! This site has good layout stability.

Is it resilient? This site didn’t have any third-party requests blocking rendering that could become a single point of failure. It had no security issues”.

Tools for checking site speed

The next step is to calculate the performance metrics of the page:

  • time to First Byte (TTFB);
  • first Paint;
  • speed Index;
  • Cumulative Layout Shift (CLS);
  • page weight;
  • visual page load process.
WebPageTest to check website speed

Next, the service suggests comparing the WebPageTest run with the performance data collected by the browser for this site, i.e., with the actual usage metrics.

What tools can be used to check website speed

The block with tables and diagrams “Individual runs” displays testing errors and navigation, the timeline of viewing, processing breakdown, viewing trace, and content breakdown. Here you can view a video of the page loading process.

WebPageTest for website speed

Another important feature is the visual comparative test. It allows entering multiple URLs, enabling their simultaneous testing and comparison with each other.

Users can save the test results — even if they are using a free account. They can share the analysis results via email or Twitter, and also view the formatted screenshot image.

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The results of testing performed by this tool include practical recommendations for improving pages and breakdowns by content size. Pingdom notifies clients about downtime and is free for the first 14 days.

For $120 per year, availability, performance, and business transaction monitoring are available. Page size, load time, and requests are analyzed. Additionally, for an extra $120 annually, you can connect a plan for analyzing an unlimited number of sites with no user limits, providing reports for shared access. This option is optimal for agencies managing various web resources and needing to monitor the results of all clients simultaneously.

Pingdom a tool to check how fast your website is

To improve page performance, the service generates recommendations based on analysis, such as “Add expiration headers”, “Use cookie-free domains”, “Make favicon small and cacheable” and so on.

How to determine the performance of a website page

The analysis includes monitoring response codes, content size, requests by content type, content size by type, and by domain.

site page speed analysis

Special icons are used to denote different types of content (text, image, HTML document, etc.). Similarly, for distinguishing HTTP response codes on the diagram, colored dots are used near the URLs, and colored indicators denote different stages of the request execution.

Site page load speed indicators
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The service uses Google Lighthouse to analyze the performance of the website, including metrics such as full load page speed, first and largest contentful paint, and more. Testing can be conducted from multiple servers.

To check the performance of the resource with different types of network connections, there is a function to adjust their quantity.

In addition to the free tier, there are packages with extended capabilities for $10, $21, $42. They include additional test servers, analysis from mobile devices, hourly and global monitoring, and more.

The tool analyzes the effectiveness and structure of the website, as well as its vital metrics that assess the user experience:

  • LCP — how long it takes for the largest content element on the page to fully render
  • TBT — the duration of script blocking during page load
  • CLS — layout shifts that occur during page load.

There are many tabs available with information about the website even for unregistered users (“Summary”, “Efficiency”, “Structure”, “Cascade”, “Video”, “History”).

GTmetrix for analyzing site performance

The service identifies key issues affecting the website’s performance, for example: “Avoiding document.write() — 1 instance found”.

how to speed up website loading

The service calculates the full loading time, the overall size of the page, and the total number of requests made to it. While these data might not always be clear to website owners or marketers and may not be decisive, they are crucial for SEO specialists or developers in improving the performance and effectiveness of the web resource.

how you can speed up the loading of your website

Using a free GTmetrix account, you can assess how your website performs in multiple regions and create an error remediation plan based on the reports provided.

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Google PageSpeed Insights

The tool is owned by Google and assesses user experience based on the Chrome UX report. Performance assessment is determined by Lighthouse using two types of data.

  1. Field data provides information about the actual experience visitors receive on the site. It’s valuable for capturing real user experience but has a more limited set of metrics.
  2. Lab data is gathered in a controlled environment to identify and address performance issues. This information is accurate but may not always reflect the real weaknesses of the web page.

For all metrics, the 75th percentile is selected, and the data is updated daily. Google PageSpeed Insights categorizes user experience quality into three categories: “Good”, “Needs Improvement” and “Poor”.

discover what your real users are experiencing

Performance issues are evaluated in percentages.

How to fix site performance problems

Alongside audits, the tool provides recommendations for speeding up page loading.

How to check a website through Google PageSpeed Insights
Nick Lukashuk

Expert comment

Despite fast internet, 4G/5G/6G coverage, and faster devices, speed remains a crucial factor in SEO, advertising, and overall website conversion and marketing investment efficiency.

In 2023, various image formats like WebP and Avif, deferred or asynchronous styles and scripts, CSS sprites, and similar techniques no longer surprise anyone. Google has introduced metrics such as LCP, FID, CLS, FCP, INP, and TTFB, in addition to the typical 90+ score or the widely accepted 2-second benchmark.

In addition to being one of the ranking factors in SEO, website speed is also considered in the quality score of Google Ads landing pages, affecting the cost per click, ROAS/CAC, and is particularly crucial for all traffic directed to the site.

Let’s analyze.

If a website gets 50,000 visitors every month, and the average conversion rate is 1.5%, then improving the website’s speed by 50% will increase the conversion rate by 10%, making it 1.65%. From the given 50,000 monthly visitors, this translates to +75 orders per month, which is +900 orders per year. For example, in ecommerce with an average order value of $100 and a profit margin of 40%, this means an additional $36,000 in revenue per year.

Make conclusions and work on improving speed.

Nick Lukashuk, CEO

The analysis results are multifaceted, structured, and accessible. In particular, there is a list of elements that need to be checked manually, tips for improving content readability, and more.

What influences the loading speed of web pages?

According to Google Analytics documentation, the method for calculating average page speed was changed in November 2011. Since then, the metric has been calculated taking into account the redirection time. The more redirects and the more significant they are, the slower the website may perform.

The speed of a web page is influenced by every element on it. This includes HTML code, CSS that styles page elements, JavaScript files, as well as images, videos, quizzes, calculators, and other components.

Let’s consider the main factors that hinder fast loading of web pages.

  • Heavy images, especially those with high DPI. The solution is to optimize images or use a content delivery network (CDN).
  • Presence of large files for users to download.
  • A significant amount of JavaScript scripts also slows down the page. Using a compression or minification tool for JavaScript reduces the download size.
  • Unused code left in the HTML code of the page, such as CSS, JS, or others.
  • Very early or, conversely, too late script rendering. This refers to the possibility of viewing the page only after all its content has been loaded.
  • Hosting location. Network delays can occur if content travels a long distance. This happens if the HTML and CSS files of the site are hosted in geographically distant data centers.

Additionally, the speed and performance of a website can be influenced by factors beyond the control of the website owner or technical specialists responsible for its technical aspects. This includes the user’s browser, type of connection, and network issues. Poor quality internet services provided by the user’s internet service provider can slow down even a lightweight and technically well-designed website.

For instance, even if a website is lightweight, it may still load slowly in browsers due to network sluggishness. The speed of connection to the network is influenced by the local network equipment used and the quality of the internet service provider’s services. Mobile devices using 3G or 4G instead of connecting via Wi-Fi often provide a slower network connection as well.

How to speed up website loading time?

The page load speed metrics are determined by a fixed sample set, representing 1% of users, as mentioned in the Google Analytics documentation. To increase the sampling frequency, you can add the setSiteSpeedSampleRate() function to your tracking code when updating content.

The plan to increase website loading speed is an important component of the technical optimization strategy for a web resource and is usually prepared by an SEO specialist based on analysis. Here are several measures that are universal and almost always help to speed up page:

  • Reducing the number of CSS files: Making fewer CSS files removes extra symbols in content.
  • Compressing images with Gzip: Using Gzip compression reduces loading time for CSS, HTML, and JavaScript files.
  • Implementing a Content Delivery Network (CDN): Content Delivery Networks (CDNs) help by delivering content from the closest server, which speeds up loading.
  • Optimizing media files: The best formats for images are PNG or JPEG. Videos can be compressed or uploaded to platforms like YouTube and then embedded on web pages using embedding code.
  • Using individual web hosting with optimized speed: Choosing a web hosting service that is fast and reliable ensures quicker loading times for your website.
  • Minimizing HTTP requests: Combining files and removing unused code helps to decrease the number of HTTP requests.
  • Enabling browser caching: Setting up browser caching for static resources on your website reduces loading times for returning visitors.

Normal image compression can save a lot of memory and make using the website faster and more enjoyable. Don’t try to place too many interactive elements on the page if they are not essential for conveying information or increasing conversions.

You can test different content, leaving in the result the one that brings the best results. For example, if visitors use the survey more often than the price calculator, then the first component is important for sales, while the second one may serve as unnecessary “baggage”. In this case, website speed analysis is informative and comprehensive only in combination with usability audits and conversion rate assessments of the web resource.

What are the most frequently asked questions about website speed analysis

How to check the page speed of website?

To check the loading speed of website pages, use services such as Google PageSpeed Insights, GTmetrix, WebPageTest, or Pingdom. Enter the URL into one of these tools, and it will analyze the loading speed and provide a report with recommendations.

How to check what slows down website loading?

The most common factors that slow down a website include large images, unnecessary JavaScript, lack of caching, and so on. Regularly check your pages, avoid adding large-resolution GIFs and images, and use WebP format whenever possible.

Website performance is measured in:

— Page speed time (seconds, milliseconds).
— Time to first byte (TTFB).
— Time to interactivity/first contentful paint (FCP, TTI).
— Total number of requests and page size (kilobytes or megabytes).
— Google Core Web Vitals (LCP, FID, CLS).


The speed of a webpage is influenced by numerous factors, from the size of each element on it to the quality of network equipment. Most of these factors can be controlled by the website owner. These include large JavaScript files, video content, outdated code and scripts, heavy images, and other files.

The goal of analyzing website speed is to create the best user experience to reduce bounce rates and increase conversion rates. Therefore, it is important to develop a strategy for optimizing page speed and adhere to it when developing and adding new pages. Technical specialists should be tasked with preparing optimization rules for images, media, widgets, and plugins.

Follow these tips: Developers should pay special attention to server speed, API usage, and caching. At least once a month, use tools to check your website’s speed.

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