More feeling please when testing the website speed

Jan Hornung Last updated on 21.10.2020
6 Min.
Website speed
Last updated on 21.10.2020

The loading time of a website is important. No question. For the user experience and conversion. But for the visitor it is not the actual loading time that is decisive, but the perceived website speed. Because a user experiences a website without knowledge of the measured values. The perceived loading time is therefore an important value for optimizing the conversion and jump rate. We show how you measure them reliably.

Everybody knows this: You have discovered an exciting new product or found the link to a supposedly exciting blog article, click on the link and it does: nothing. It site remains white for a few seconds and then the page components build up agonizingly slowly. Buying or signing up for a newsletter is site rather unlikely on such a site.

The colleagues of Kissmetrix have been studying the relationship between page load time and the conversion rate in shops for some time now. The result: every second counts. Because the average visitor is impatient. This means that a charging time that is one second longer can already be achieved in a seven percent lower conversion rate result. So with every second that yours site takes longer to charge, you lose sales.

An antidote can Above the Folder Optimization be. So the optimization of the loading time of the area of the site . This measure reduces the perceived loading time, which in turn can lead to better conversion rates.

But how can the perceived website speed be measured correctly? Sure, you can just load them site into an incognito tab and try to feel the difference to ... well, you know. Or you can rely on a tool that gives you the perceived loading time as a tangible and comparable value.

GTmetrix is such a tool. It allows you to measure what I think is the most important load time value of yours site and makes it comparable. It is very easy to use and provides valuable measurement data.

This article is part of a series on the topic of charging time measurement:

  1. In part 1 we show why the type of data a test provides is so important
  2. In part 2 I show why the popular PageSpeed Insightstest is absolutely unsuitable for performance comparisons
  3. Part 3 shows you what data you need to be able to make a good performance comparison - e.g. after a change of hosters

GTmetrix: Many optimization recommendations, history of website speed and video function

Using GTmetrix is very easy: You enter the URL of the one you want to test site and the tool spits out the result after a few moments. The disadvantage of this:

  • GTmetrix offers only one server location, Vancouver
  • GTmetrix tests only with Firefox

This means that the measurement results of GTmetrix are always valid for a visitor from Vancouver who accesses yours site via a desktop computer and Firefox. As long as you work exclusively with GTmetrix for your performance measurement, this does not affect the results. But if you want to know how fast it site loads for European visitors, you have to use another tool.

GTmetrix will give you four large data packets:

  1. The overview with the potential analyses and important key data
  2. The waterfall diagram
  3. The (chargeable) video function
  4. The time series analysis

The special feature of the overview: It provides the results of two potential analyses at the same time

In this overview you will find all the important key data of yourssite . In addition to the potential analyses by Google (1) and Yahoo (2), you will find under Page Details the page load time (3), i.e. the load time of your pagesite , the size of your page (4site ) and the number of HTTP requests. (5)

By the way, the loading time and the HTTP requests are particularly suitable for comparing the performance of two websites or website versions.

Measure website speed correctly with GTmetrix: An overview
Under "Test Server Region" and "Using" is clearly visible: In the free version GTmetrix uses a server in Canada and the Firefox browser to determine the website speed. For European sites this test setup means longer loading times.

This first overview also includes the detailed results of the two potential analyses PageSpeed Insights and YSlow. These show exactly how well it has been optimized so site far and where there is still room for improvement. The fact that GTmetrix uses two different rule sets (one from Google and one from Yahoo) is commendable. Because this offers you as a user more orientation. If an optimization measure is suggested by both tests, it is most likely an important optimization step that is worthwhile to work on.

The perceived website speed is important. The overview of the potential analysis of GTmetrix shows you where there is room for improvement.
This is what the potential analyses at GTmetrix look like. Nothing new, if you have ever seen a Google PageSpeed Insightsresult or the results of YSlow. Using a dropdown you can display detailed information about the individual steps.

In its help section GTmetrix offers detailed descriptions and interpretation aids. This makes it very easy, especially for beginners, to familiarize themselves with the complex result structures.

The waterfall diagram is the heart of the analysis

Just like Pingdom GTmetrix only reveals the really interesting data in the so-called waterfall diagram. This breaks down all loaded data packets (1) in chronological order (2) and with their loading time (3). In addition, the type of call is displayed (4), whether the respective request is OK (5) and whether the server issues an error (6).

Detail view of a waterfall diagram from GTmetrix for website speed analysis.
The waterfall diagram shows in detail which factors have which share in the website speed.

This detailed information now allows reasonable performance comparisons to be made between twosites . This becomes relevant, for example, after a change of hosters or onpage optimization. It is important that the measurements always take place from servers in Canada and via the Firefox browser. If you want to test other parameters, you must either buy GTmetrix or use another tool, for example webpagetest.org.

The detailed view of the loading time provides an even more accurate picture of the individual data packets and their contribution to the website speed. In the example: the first contact with our server. 5 milliseconds are needed for the DNS lookup, 167 milliseconds are needed for the client to connect to the web server, after 172 milliseconds the first data is downloaded. The long waiting time of more than a second is partly due to the geographical distance of the test server from the actual server location. The test therefore provides the data for a customer from Canada.

Details from a waterfall diagram to analyze the website speed
Detailed breakdown of the first request of the browser to the web server.

Most important advantages of GTmetrix: Time series analysis and video function for the perceived loading time

Compared to the tool I presented a few days ago, PingdomGTmetrix offers two decisive advantages:

  1. a free time series analysis
  2. a video analysis with costs

1) The time series analysis

Comparing the loading time of your site files over several days or weeks can be very informative. For example if you optimize your site step by step over several weeks. The history function offers this time series information (in the free version) for three dimensions: The load time of the site , the number of HTTP requests and the size of the site and the scores of the potential analyses YSlow and PageSpeed Insights.

Time series comparison of website speed for GTmetrix
Not to be seen in the picture: the time series analysis of the potential analyses. However, these are not relevant for the website speed at first.

2) Video analysis - the only real indication of the perceived page load time is unfortunately subject to a fee

Now we finally get to the feature that makes GTmetrix so valuable. And also better than Pingdom, for example: the video function. In such a video the page structure is shown. Sure. But this simple trick allows a clear differentiation between the measured charging time and the perceived charging time. Unfortunately, the tool is only available after registration with GTmetrix (and probably also after purchasing the service). It doesn't have to be, because webpagetest.org offers this video function free of charge, for example.

Conclusion: A real professional measurement needs information about the perceived loading time

The video function is elementary for the analysis of the loading time and especially the loading time experience of the users. It allows comparisons on a level abstracted from the mere data. We can only recommend tests that allow video analysis. Because under certain circumstances the measured loading time is quite high, but the perceived loading time is absolutely justifiable. The value not only allows you to better understand how customers or users perceive your offer, but also whether a page optimisation is worthwhile with regard to performance. Under certain circumstances it may be worthwhile to invest more in conversion optimization than in the loading time of the site .

All in all, GTmetrix is another good tool to measure the loading time of site the. It offers some more information than Pingdom, as the free version of GTmetrix includes two potential analyses at once. The really interesting features are hidden behind the payment barrier, but they are there in principle, so GTmetrix allows you to understand the performance of yours site very well and also to monitor its development.

But for us GTmetrix is not the number one free tool. Because it gets even better: webpagetest.org is for us the non-plus-ultra of free measurement tools. However, the tool also places the greatest demands on the user.

Have you already had experience with other measurement tools that might provide even better data?

RAIDBOXER of the first hour and Head of Support. At Bar- and WordCamps he likes to talk about PageSpeed and website performance. The best way to bribe him is with an espresso - or Bavarian pretzel.

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