Why You Need to Optimise Your Mobile Site Speed for SEO & User Experience

Reading Time: 8 mins

Why does your website need to be fast on mobile devices? Well consider the fact that potential customers are 5 times more likely to leave or hit back on a mobile website which loads slowly and isn’t mobile-friendly, and you can imagine the number of customers you may be losing out on. Customers which may very well be going directly to your competitors who have mobile-friendly sites that load quickly.

So what other reasons are there for optimising your mobile site speed?

SEO Purposes

Back in 2010, Google announced page load speed is part of the ranking algorithm. But now the focus is more on mobile, it’s mobile page speed that’s key to a better experience.

From July 2018 Google is using mobile page speed as a ranking factor in the mobile search results. This is big news for businesses whether they have mobile-friendly websites or not.

Google stated the following:

The “Speed Update,” as we’re calling it, will only affect pages that deliver the slowest experience to users and will only affect a small percentage of queries. It applies the same standard to all pages, regardless of the technology used to build the page. The intent of the search query is still a very strong signal, so a slow page may still rank highly if it has great, relevant content.

While it may not have the biggest impact on your standings, it will certainly have an impact on what happens once a customer clicks your result. And thus, whatever they do next could impact your rankings – whether they bounce or find what they need.

Google knows better page speed creates a better experience for users of Google. So it is simply providing the best experience it can.

Mobile-first Index

And if you needed any more encouragement to optimise your website for mobile users, Google’s recent switch to a mobile-first index should be the final nail in the coffin.

While rankings used to be based on the desktop version of your website, as that is the version Google’s crawlbot would crawl, now it ranks your site based on the content that loads on the mobile version of your website.

That means that if the mobile version of your website is stripped down, you may see a fall in rankings.

Increased conversions

If your website isn’t optimised fully for mobile browsers, then your website won’t be a good place for a potential customer looking to convert. Speed is a big part of this.

Whatever this action is – whether it’s filling out a form, purchasing a product or otherwise – it’s likely to be a difficult task unless you have truly optimised the path for someone on a smartphone or other mobile device.

Any CTAs and interactive aspects of your website should be clear, easy to click, and simple to use.

Google stated:

60% of online users say that thanks to online research, they make purchase decisions more quickly now than they did a few years ago

Mobile users use websites differently – and it needs to be efficient

Not only is the nature of how someone navigates a website significantly different when on a smartphone compared to a desktop, but there are other things to consider.

The objectives and intent of a smartphone user is likely very different to someone on a desktop.

Mobile users will be looking for a quick answer or browse, with content broken down in digestible chunks.

Purchases on a mobile are also more likely to be “impulsive” – which can be a big positive for ecommerce retailers looking to boost sales.

Desktop users are likely to do more, in-depth research, and also be willing to read longer, more informative pieces of content. If they are on a desktop, they are more likely to be around for a while – rather than quickly double-checking or fact-finding on a smartphone.

Think with Google

Minimise your bounce rate

Site speed is a big reason behind why people will stay on your website, or leave it within a few seconds.

Whether your website looks great and is readable on a laptop or desktop is one thing to consider. But if it isn’t simple to use on a mobile phone then your bounce rate is likely to be significantly higher than it could be.

Mobile users won’t be staying around on your website if they can’t read your content, have to zoom and pinch to navigate your website, or cannot use certain aspects of your website altogether.

Bounce rate is still an indication to Google as to how relevant your website is to the search results, and therefore how useful it is for the people visiting your website. If everyone is hitting the back button once landing on your website, Google will likely drop your rankings down, as people are clearly not liking what they are finding.

Of course, this could be down to the content, search intent, or a myriad of other factors. But one of these is mobile-friendliness and how well optimised it is for the device it is viewed on. I’m sure everyone has hit the back button after landing on a website that is simply unusable on their smartphone. Why would you continue to use a site that is unoptimised when there are numerous other sites or potential competitors that do a better job?

Ensure your website is mobile-friendly to bring down your bounce rate, keep potential customers on your website, and improve your overall SEO.

Google/SOASTA Research

Reduce page load time

If your site is quicker, page load time is faster, and is yet another factor for SEO. This also helps improve the overall user experience.

Google themselves have said:

People’s patience for a cumbersome and clumsy mobile site or app is waning. They expect to move through a brand’s mobile experience at lightning speed. There are a few simple steps marketers can take to eliminate speed bumps and ensure every customer’s need for speed is met.

Think with Google


While SEO may not be the only reason to improve your mobile site speed, mobile site speed will also play a big part in your bottom line – especially from business done on mobile devices.

And as Google is so keen on mobile traffic, it’s likely that mobile site speed will play a more significant part in Google’s search rankings in the future. July 2018 will certainly see interesting things happen.

For now, what can you do next? Google’s advice is as follows:

Resources that can be used to evaluate a page’s performance.

  • Chrome User Experience Report, a public dataset of key user experience metrics for popular destinations on the web, as experienced by Chrome users under real-world conditions
  • Lighthouse, an automated tool and a part of Chrome Developer Tools for auditing the quality (performance, accessibility, and more) of web pages
  • PageSpeed Insights, a tool that indicates how well a page performs on the Chrome UX Report and suggests performance optimizations