Why Site Speed Matters

An article by Darrell Wilkins on 22 Feb 2021

Summary: Website speed directly affects your business performance. Fast loading sites have better user experience, drive more conversions and rank higher for SEO. People perceived slow loading sites as less credible, lower quality and more frustrating.

You don't need lots of academic research to tell you that slow websites are annoying. You'll have experienced it for yourself. But you might be surprised at how they can affect the bottom line.

49% of consumers expect a page to load in 2 seconds or less.

53% of mobile site visits abandoned after 3 seconds.

A 1-second delay in page load time equals 11% fewer page views, a 16% decrease in customer satisfaction, and 7% loss in conversions.

The benefits of a fast loading site

The most significant determinant of a website's success is the experience that your users have.

If a user can't find your site, they can't use it. And if they abandon your site before doing anything, you lose a customer. So even before your visitor has engaged with your brand, page speed plays it part.

Site speed and SEO

Speed has been a Google ranking factor since 2010, albeit a minor one. In 2018 they extended this to mobile search. There is another major update to Google's algorithm coming in May 2021, and we expect it to have a much more significant impact on slow sites rankings.

Google is broadening the performance criteria against which they will be judging your site. They call it Core Web Vitals and will be measuring:

  • Largest Contentful Paint (LCP) How quickly the largest image or text block becomes visible. Less than 2.5 seconds is considered good.
  • First Input Delay (FID): The time elapsed before a user can interact with your page. It should be under 100ms.
  • Cumulative Layout Shift (CLS) How much elements move around on the page as it loads.

Google have a tool to help you check your Core Web Vitals. If you score under 80, get in touch, we can help.

Google has given notice of the change, which is significant; they usually don't. You should expect your Core Web Vitals scores to impact SEO performance when the change happens. Or, put another way, if you want your customers to find you, improve your site's speed.

Website performance and abandonment

People are impatient. When they visit your site, they are focused on a particular goal. That might be to learn about your product, sign up for an event or find your contact details.

Users are incredibly sceptical when visiting a new site. They have been exposed to countless slow and poorly designed sites in the past. They have learned that most pages they see are useless, or rather most pages don't deliver on expectations.

The first 10 seconds of the page visit are critical for users' decision to stay or leave. The more time wasted loading, the shorter time you exposed users to your content. And that makes them more likely to leave.

One measure of abandonment is bounce rate. It's the percentage of visitors who enter your site and then leave without viewing any other pages.  Deloitte has done research that showed a 0.1s (a tenth of a second) improvement in speed led to an 8.3% improvement in bounce rate for lead generation pages.

And that 70% of consumers admitted that page speed impacts their willingness to buy from an online retailer, with 10% blaming slow downloads as a reason for not purchasing.

Speed sells

It's not just that slow sites make it harder to be found or cause visitors to leave. The same 0.1s improvement in load time resulted in:

  • A +21.6% increase in form submissions for lead generation.
  • A 10% increase in conversions and a 1.9% increase in average order value in the travel sector
  • A 40% increase in 'adding to basket' on luxury sites.

Why does a slow site have such an impact?

Because we are human beings.

We know when interacting with technology, if something happens within 0.1s, it feels instant. If something happens in under one second, while we notice the delay, our thought flow is just nudged, not interrupted.

Past two or three seconds, that flow of thought is interrupted, and this causes frustration. Frustrated people leave your site, or buy less, or judge your brand negatively.

Human perception is a funny thing

Objective measurement is one thing, but humans form judgements based on their perception of the world. Once you understand them, you begin to see why speed is such a big issue. Luckily lots of research has been done:

  • We perceive load times as being 15% longer than they are.
  • Not only that, but we remember them as being 35% longer.
  • Faster loading sites are perceived to be both more interesting and more credible than slow-loading ones.

Users remember a slow experience as a worse experience than it was.

It matters even more on mobile

Most sites already have over half of their traffic on mobile devices, even corporate B2B sites. And if they don't yet, the trend line is pretty clear.

Yet most sites are designed for the Desktop. They are often 'responsive' designs which mean they work well visually at smaller screen sizes. However, mobile devices are much less powerful and have more constrained network connections. The files that make up your site arrive slower (granted not by much with modern networks), but it takes far longer for the processor in a phone to render a page than a desktop machine.

The same site, which may load reasonably well on a desktop, will load far slower on a mobile device. The good news is that if you can make your site load fast on mobile, you'll have no trouble at all on desktop machines.

How fast do you need to be?

Nobody ever asked for a slower loading website. And as discussed above, it's not just about speed. Cumulative layout shift (CLS) is an essential factor to consider. That said, Google believes that any page load which takes over 3 seconds needs improvement. Considering our company name, you might be unsurprised to learn that we think 2 seconds is the upper limit.

You really can't have a site that loads too fast, so it comes down to economics.

Once you've got a page-load of under two seconds, then you are into optimisation. For large scale sites doing tens of millions of pounds in revenue, it is worth investing in those tiny 0.1s improvements. Another business may judge that the budget would be better spent on UX improvements or better content.

The sweet spot is where your conversion rate and revenue are maximised.

What can you do about it?

Firstly you need to understand if you have a problem. There are lots of free tools available to test your site performance. Page Speed Insights from Google is an excellent first stop; GTmetrix and WebpageTest are also good options.

Each tool does a slightly different thing, and the results can be a bit confusing. You might score well on one site and less well on another. Each test will also give you a list of issues with a somewhat vague recommendation for improving things.

Some problems like oversizes images, minifying javascript, or a slow server are easy things to fix. Other issues are more fundamental. Your choice of content management system, the front-end technology choice and even the way the HTML is written can affect performance. You'd be amazed at how much you can improve an existing site. Sometimes only a rebuild will get you there.

The fastest sites are built with performance in mind. So if you're looking to improve user experience, climb the SEO rankings or increase your conversions, put site speed towards the top of your priory list.