How Site Speed Affects Conversions

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Wondering why your conversion rate is so low? Your site speed may be to blame.

In our busy lives, anything that takes a bit longer than expected is liable to put us off – whether it’s buying something online or simply looking for information.

How much of an impact your website’s speed has on your potential customers and clients is clearly shown in data and case studies from the likes of AkamaiBacklinkoMachmetrics and Google – all demonstrating that the longer a page takes to load, the more likely you are to lose visitors to your site.

It hardly needs to be stated: once you lose visitors, you lose conversions, and you lose business revenue.

It’s all very well reading the data, but do understand how website speed affects conversion rates in your business?

Discover how website speed can affect your conversion

What Is Page Speed and Why Does it Matter?

If you open a website page on a computer, it takes an average of 1.3 seconds for the first byte to load. The average time it takes for the entire page to load in 10.3 seconds.

On a mobile device, it’s an average of 2.6 seconds for the first byte, and 27.3 for all the content to load.

The faster the page loads, the more your visitors will hang around – giving you a lower bounce rate.

Think With Google data for page loading speeds on mobile websites shows how dramatically page load speed can affect your bounce rate:

  • 1-3 seconds: the probability of bounce increases 32%
  • 1-5 seconds: increases 90%
  • 1-6 seconds: increases 106%
  • 1-10 seconds: increases 123%

Why does all this matter? You want to minimise your bounce rate so that you can improve your chances of keeping potential customers or clients engaged – with the ultimate goal of converting their interest to business.

Fast website loading is also key to good Search Engine Optimisation. Google and other search engine crawlers ‘reward’ quicker page load times, so a fast site is more likely to get a higher organic ranking on search engines.

How Website Site Speed Affects Your Business:


53% of all users leave a mobile site because the page is loading too slowly, says  Google in its 2018 research.

And 70% of customers say their decision to purchase is affected by load times – according to data published in the Search Engine Journal.

Even a one-second delay in your page load can have a 7% reduction in conversions. Sounds like a small percentage, but it adds up.

Let’s say an e-commerce site normally makes £100,000 per day. A one-second page delay could potentially cost the business £2.5 million in lost sales every year.


The user experience (UX) on your website is an intrinsic part of how your customers view your business. Slow loading times and difficulty navigating a site can result in a negative opinion of your brand – not only will they leave your page, but they may never revisit your site. 

Akamai’s report for retail businesses says that 28% of dissatisfied online shoppers are more likely to develop a negative perception of the company, and 27% will tell their friends and family about their bad experience.

It stands to reason that this applies across all industries, not just in e-commerce.

How Does Website Speed Affect SEO?

The usability of your website doesn’t just have an impact on your visitors – it affects your visibility on search engines.

Google introduced an algorithm in 2018 that means page speed affects your ranking, so the faster your pages load (particularly on mobile devices), the more visibility you have in search engine results, as it all ties into the overall goal of improving user experience.

The Difference Between an Optimised Mobile Site and a Desktop Site

Mobile devices generally have slower processors than desktop computers – which means sites open more slowly on mobile.

Mobile devices are usually set to resize images in the browser, so any mistakes in mobile optimisation on your site can slow down your page load speed.

Placing ads in mobile-friendly locations on your page is also key to ensuring higher ad rates, so your advertising revenue doesn’t drop off.

On top of this, Google’s algorithms reward sites that have faster loading times, particularly on mobile sites.

Factors To Improve a Website’s Page Load Time

Research in 2018 shows that most website pages are in the range of 1.3 MB to 2.5 MB, despite a recommendation of under 500 KB.

If you have a slow site, reducing the file size is the single biggest change you can make, but many other elements can help to improve your page speed, including:

  • JavaScript Timing – working out which elements of your pages are causing a slower load, then rewriting the JavaScript code to improve the speed.
  • HTML & CSS Structure – assessing the performance of HTML documents and Cascading Style Sheets (CSS) on your site, and restructuring it to ensure that the critical ‘above the fold’ content loads first.
  • Minification & Script Compression – reducing the amount of code in your site to improve the speed of your website.
  • Themes and Plugins – themes alter your site’s layout and visual style, while plugins add different features and functionality. While it is tempting to have a highly creative theme, and lots of plugins, both can make your pages load more slowly.
  • Image Size – reducing the size of your images can help your site load more quickly – especially on mobile devices.
  • Expired Headers – removing headers that are no longer relevant – particularly on your landing pages can allow you to increase valuable above-the-fold content and improve your search engine results.

How TSCA Can Help

TSCA is a specialist technical SEO agency that offers website page speed optimisation as an integral part of our SEO, conversion rate optimisation, and web development services. To discuss site speed optimisation and how it could give your business a boost, get in touch with us!

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