When does site speed start to affect conversions?

Martin Lundvall

Most people already know that site speed affects their conversions, but most don’t care since it’s a less than sexy area often associated with IT-infrastructure and maintenance. However, if you WANT to improve your site speed today, you can no longer afford to ignore these areas. In this post we will explain why you should care and how you can do so.

There are tons of examples of how a site’s speed affects conversions and how fast visitors expects your site to be. The short version is:

The site speed impacts your conversions and the visitors expects a site that loads quickly.

Also, site speed is an SEO factor that Google looks at when it comes to ranking.

Furthermore: Google has started using Mobile First indexing

Google has started to index and SEO rank search results based on the site’s mobile content and experience, so it’s not only desktop that counts anymore. This means that site speed (and the overall experience) of your mobile site will also affect SEO in a new, more difficult way. Read more here.

Your site speed can be compared to your conversion rate: External factors will matter and you always want to compare them to yourself. Benchmarks are good tools that can show you the way. Below we will give examples of different sources and takes on what constitutes a “good” loading time, and which aspects affect how it’s measured.

1How fast are sites normally?

A study from Radware 2015 shows that the top 100 e-commerce sites have an average loading time of 5.5 seconds (desktop), while visitors expect it to be 2 – 3 seconds. At the same time, 9 out of 10 mobile users expect mobile sites to load quicker then desktop sites.

SleeplessSites are expected to be faster, but at the same time, they are growing. Just between 2014 – 2015 the average site grew with almost 70%. We add more content, images, videos and other things that makes our sites grow and in turn makes them slower. This increases the need to actually optimize and trim the site speed.

According to Pingdom:

Pingdom has created the following benchmarks for this post, where they’ve checked the average loading times of sites with optimal conditions:

  • The world’s top 100 e-commerce sites are done loading in – if they’ve been optimized – in 2.51 seconds.
  • The top 100 newspapers and magazines load at a whopplingly slow 4.6 seconds.
  • Compare this to 5.48 seconds for the biggest blogs.

But what does optimal conditions mean? Simply put, your site speed is affected by the visitor’s internet connection, your time to first byte, which in turns has to do with how long it takes for servers to respond etc. All these factors make it so that different sources have different bench marks, based on their conditions.

Don't put lipstick on a pig

The bottom line is: it’s a good idea to improve your site speed. The loading time you should aim for depends on a whole lot fo things. Good, so what should we do then?

2 Find out how bad your site speed really is

First and foremost, you want to know how bad things really are. There are a number of tools which can help you with this that show either your loading times or points to improve. We recommend that you use a combination of these. You should also use:

1. Google Analytics

Analytics gives you further data on your site’s speed. You can use segments to navigate your way through problems and see what is causing them. Are there problems regarding mobile or desktop, in a specific browser or is a specific landing page performing badly?

You will find these reports underneath Behavior -> Site Speed
(Click to zoom in)
Site speed GA report

One thing that’s good to keep track of is the page load sample, which shows how many views Google used to calculates all the values. Google actually only test things on about 1% of visitors. If you have relatively few visitors on your site, you might need to increase this sample so that you have more data to base decisions on.

We looked at Swedish e-commerce site’s (about 4 million samples) loading times in Analytics during 2016 came to the following conclusions:

  • The average loading time for Desktop is 4.2s
    (that is 1-2s slower than what visitors expect)
  • Mobile loading times are 1.6s slower than desktop (which is where visitors expect the mobile site to be faster)
  • Mobile site speed has decreased by 1.2s compared to 2015 (from 7.0 to 5.8)

2. Check your site in Pingdom for example

Through Pingdom you can get data which tells you how your site is performing for each real time user, which is a great way to monitor how different visitor segments are affected by different site speeds. You can also set up alerts for, among other things, site speed.

loading times from pingdom

To quickly run tests on a url, you can try it here for free.
Free Pingdom test

3. Do a WebPagetest

WebPagetest is an advanced tool where you get access to a number of metrics. One great function is that you can see a video of which elements load first and get a better understanding of what the user experience is like, site speed wise. You can also see how your site ranks compared to the top 300 000 sites in the world. With this tool, it’s easy to see how your optimization changes affect your ranking.

3How to optimize for better site speed

Okay, now you know more about what happens, but how should you act to in order to optimize your site speed?

1. Pick low hanging fruit through the Google Speed Testing Tools recommendations.

Maybe you can’t fix everything that is recommended at once, but the suggested improvements are prioritized, so start by crossing these off your list. You’re bound to find a bunch of low hanging fruit here, such as:

Use the tool to find what you need to work on.

Go to the Google Speed Testing Tool

Page speed test

2. Adapt your mobile content: focus and scale down!

It’s easy to think that a responsive site will solve all problems in our multi-device world, but no. The problem occurs when we keep adding more content to desktop because we have very good internet connections nowadays. But we forget that mobile users don’t have the same high quality connectivity, or that they don’t have the same needs or user patterns.

Take some time to reflect (look at user data): What are your mobile users’ most important goal? What do mobile visitors actually do on your site? Scale down and remove any unnecessary fluff. Remember: smaller site = faster site speed. Do your visitors for example use your mobile site to look for contact details, or the nearest shop? If that is the case, remove the latest news section, irrelevant videos about your vision and so on. However, don’t forget to first identify which parts of your site are relevant for your mobile visitors, and as always: test, analyze, improve!

3. Loading content when scrolling (Lazy loading)

Instead of loading the entire page at the same time, JavaScript lets you load what is immediately visible to the user and let’s you load the rest of the script as they scroll further and further down the page. The user will then think that the site loads faster.

Pingdom also recommend doing this, and suggest that you reflect on what elements are visible first on your site, since the visitors’ experienced loading time correlates with the possibility to interact with the website. One example is to load the search bar and menu early and load the “pretty” content after that.

4. Use CDNs (content delivery networks)

A CDN provides your users with several different nodes spread out across the globe, where they can download content (for example images and JavaScript). This increases the site speed since a node’s server can be much closer to the user and has cached content.

CDNs are a service that you buy from a third party, and the cost will be used much more efficiently if you go through the previous steps first.

5. Consider using AMPs (Accelerated Mobile Pages)

– Can Google’s new mobile standard speed up your site?

Google, together with many other tech companies, have created AMP. A new standard for speeding up mobile sites. The standard is still pretty new, and news sites are the ones who’re primarily using it, but many other types of sites (including e-commerce sites) can use it.

Facebook are using instant articles, which is basically the same thing.

In short, the AMP standard will adapt which types of HTML elements can be used on your mobile site, third party JavaScript is not allowed, and AMP sites are cached by Google to make sure that they are rendered faster. Things that usually slow down site speed, such as pop-ups and third party JavaScripts, are not simply not allowed or are very restricted.

AMP serp GoogleIs AMP right for you?
This project is still at an early stage, so starting to use AMP now means that you will have both a desktop site and a mobile site to develop and maintain. AMP is, right now, suited for people with a lot of time and resources, who want to be at the top of their game and experiment to improve the user experience. So, if you have limited time and resources, it is probably wiser to stand by and let the standard develop into something less time consuming. While you’re waiting, you can optimize and improve your current site’s loading time.

The Washington Post tested AMP and improved their loading time by 88% . At the same time, you should be aware that the AMP standard, along with Google, will dictate the terms and limit you when it comes to what you can and can’t do with your own site.

4Set a performance budget for continuous optimization

Good, you’ve done a heck of a job to improve your site speed. But then what? As with conversion rate, you’re never really finished (sorry!). What can you do to make sure that you don’t forget to work continuously with site speed?

Start making a performance budget. This means that every change or project that involves new functions on your site, or if you re-launch it, should have clear goals and guidelines regarding how they affect the site speed. This makes everyone involved aware of the fact that site speed is important. This way, site speed will be included in any changes made and will be followed up.


There is a lot you can do to make your site faster. However, the most crucial part is to make sure that you actually start. Get going with these three steps:

  1. Find out how slow your site really is through using for example Google Analytics or Pingdom
  2. Start optimizing the areas that Google suggests
  3. Keep the site speed focus through continuously working with a performance budget

Read also

Conversionista is open for business in The Netherlands.
Conversionista is open for business in The Netherlands. Read more.