Does site speed matter?
A slow loading webpage creates a poor user experience, but does it really make a significant difference if you have an awesome proposition, product or website? Well, Google discovered that page speed does matter big time and it shelved a potential improvement to its search engine results page as a direct result.
After listening to customers in research express a clear preference for 30 rather 10 results on Google search, Marissa Mayer, Director of Search Products and User Experience, decided to A/B test displaying these two options. The experiment showed that displaying the extra 20 search results increased the time for the page to load by 0.5 seconds. Shockingly this led to a 20% fall in full page renders when 30 results were displayed. In other words one in five users searching on Google were not willing to wait an extra 0.5 seconds for a page to load.
Research by Google indicates that mobile users are even more sensitive to page loading speed. A page load time of between 1 to 5 seconds means the probability of a bounce increases by 90%
So how quickly should a webpage load? Research for Akamai and Gomez.com found that almost a half of users expect a site to load in 2 seconds or less and that many will leave a site if it hasn’t loaded within 3 seconds. This demonstrates that users have relatively high expectations and could help explain the impact on conversion of slow loading websites.
As a rule of thumb if your site loads within 3 seconds that is pretty good performance. More normal is between 4 to 7 seconds, but don’t be satisfied with that, look to reduce it. Anything more than 7 seconds and you definitely should be looking to take action to reduce the time your visitors have to wait to interact with your website. You should seek to reduce load speed provided the ROI makes sense. This can be assisted by A/B testing identical pages that have different load speeds. Provided you see an uplift that outweighs the cost of improving the load speed then it is worth continuing the process.
How to measure load speed?
All web analytics tools should allow you to see your individual page load speeds. If you are using Google Analytics go to “Behaviour” and select “Site Speed” and “Page timings”. In the drop down menu select “Average Document Interactive Time” as this is a measure of how long before a user can begin to interact with the page. This is a more meaningful indicator of load speed as many sites have content loading in the background well after the page appears to have loaded to a visitor.
Other tools to measure load speed:
- Google Developers: A Free resource that rates your page speed for desktop and mobile devices. Generally your site should get a score of over 80 to be performing well, but see how you compare to your major competitors to benchmark your site speed. It also provides recommendations for the main areas to investigate to improve your load speed.
- WebPagetest: A Free tool for the more technically minded user that allows you to define the geographical location and to test different in different browsers. This gives you a detailed breakdown of the load speed of individual elements on the page.
- OctaGate Site Timer: Provides a Free evaluation of the impact on load speed of images, frames, iframes, script files and it also follows redirects. It also helps you identify the key offenders for you to optimise.
- YSlow: This gives you a Free analysis of load speed and indicates why page speed is slow based upon Yahoo!’s rules. It also enables you to select the browser you wish to test the page in.
How to speed up your site:
1. Minimise page size:
1.1 Use GZIP compression – Check if your web host is using GZIP compression and deflation as this can reduce file size by up to 70% without adversely affecting the quality of images of videos. Enter your site URL into the GZIP test tool to find out if your site is already GZIPPED.
1.2 Use JPEG rather than PNG images – PNG images don’t compress photographs anywhere near as much as JPEG files can and so make sure you use JPEG’s when you can. Smaller file sizes can help improve load speed markedly.
1.3 Adjust JPEG image quality – By setting the image quality of JPEG’s to 50-75% you can often significantly decrease the size of your images without any obvious reduction in image sharpness.
1.4 Avoid single page websites – Trying to get all your content on a single page is problematic at the best of times, but it also tends to result in very slow loading times because the page is often long and there are no other page to move content to.
1.5 Remove extraneous metadata from image files – Designers often leave a lot of metadata in image files, including comments, thumbnails and other information that they may find useful, but just adds to the file size. Get your designer to create a backup a copy for themselves and then put the website image version through image optimization software to minimise the file size and remove ancillary chunks.
2. Reduce the number of browser requests:
2.1 Enable browser caching – Provided your page dependencies don’t change too often you should look to enable browser caching so that the browser doesn’t have to dynamically generate the page every single time it loads. Contact your server admin or if you use WordPress you can use plugins like WP Super Cache to significantly improve page load times.
2.2 Use CSS sprites to combine small images into one file. Most websites have lots of small images (e.g. logos, icons, buttons etc.) which normally have to be fetched individually from the server. CSS sprites significantly improve performance by combining all the small images on a page into a single file called a “sprite”. This reduces the overhead of having to fetch multiple image files.
2.4 Minimise the number of redirects – Multiple 301 redirects can confuse your browser and slow page load dramatically. Be careful not to create too many redirects as this can kill load speed.
3. Minimise the distance to your site:
3.1 Reduce the distance to your site – If you have users spread out around the globe consider a Content Delivery Network (CDN) to allow access to a server near the geographical location of your visitors. CDN providers such as Amazon Cloudfront and Softlayer provide competitive CDN services that can significantly improve site load speed.
The evidence is clear – load speed is an important driver of bounce rates and conversion. Don’t let a slow site speed harm your conversion rate as there are plenty of ways to improve load speeds. Make sure you regularly check our site speed and use the above strategies to improve your site’s performance. It could make a large difference to your conversion rate.
Here is a great infographic from Skilled.co on how load speed affects your website.
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- About the author: Neal provides digital optimisation consultancy services and has worked for brands such as Deezer.com, Foxybingo.com, Very.co.uk and partypoker.com. He identifies areas for improvement using a combination of approaches including web analytics, heuristic analysis, customer journey mapping, usability testing, and Voice of Customer feedback.
- Neal has had articles published on website optimisation on Usabilla.com and as an ex-research and insight manager on the GreenBook Blog research website. If you wish to contact Neal please send an email to firstname.lastname@example.org. You can follow Neal on Twitter @northresearch and view his LinkedIn profile.