It's not enough to just have a mobile optimised website, it's vital that its performance meets customer expectations. 

Speed (or lack of) kills conversions on the web, and it's no different for mobile.

In fact, with differing performance levels by device, and variable mobile internet connections, it's even more important to keep mobile sites light. 

Here is some great advice taken from our Mobile Websites and Apps Optimisation Best Practice Guide, authored by Belron's Craig Sullivan....

Mobile performance and customer expectations

A few years ago, just having mobile internet was a novelty, but now customer expectations on performance have changed. 

Stats from Gomez show that the majority of users expect performance levels close to that on desktop: 

The stats also show that: 

  • 74% of users will abandon after waiting five seconds for a mobile site to load. 
  • 57% have experienced problems when accessing a mobile site. 
  • 46% would not return to a poor performing site. 

If your customers are using Wi-Fi for their mobile device connection, it‟s interesting to see how many people are sitting at home. I know, because a huge proportion of our mobile site visits come from recognisable UK internet service providers.

This multi-screening – with TV, laptop, phone – is something that is fairly common these days.

However, if you don‟t have a decent Wi-Fi connection, the data speeds your customers get will vary hugely when they are using mobile data networks. Even in central London, where you would expect a decent signal, it can be very poor. 

According to Aberdeen Group

A 1-second delay in page load time equals 11% fewer page views, a 16% decrease in customer satisfaction, and 7% loss in conversions. (In dollar terms, this means that if your site typically earns £10,000 a day, this year you could lose £250K in sales).

There are some cool hobbyists who are really into measuring the speed of mobile phone networks. They‟ll drive around for a few hours with their phone in the car, and map out the download speeds they get during the ride.

There are a number of people developing maps of the performance across the UK – from a signal and a performance perspective.

Aside from actually needing to stay in more and watch TV, these brave hobbyists learn what we all experience on mobile surfing – speed varies heavily, even when you get a 3G connection.

Sometimes page loading is glacially slow, like stuffing a pig down a toilet using a twiglet.

I'm tired of mobile sites that take 40, 60, 90 seconds to load, because they are bloated and I don‟t want to wait. Why should they be big, like a desktop site? Can‟t they be smaller and faster?

Keeping page size down

Don‟t be swayed to include fancy graphics or pages that take a long time to download. Speed is absolutely vital on mobile, as it impacts hugely on conversion rate, page views and other metrics.

If the customer has a less than optimal data rate, every byte on your site you can remove will improve their experience, conversion rate and raw satisfaction.

According to more stats from Gomez, on November 15 last year,  the average response time for 14 industry-leading mobile retail sites was 4.73 seconds. Amazon led with a response time of 2.85 seconds. 

Conversion rate increases 74% when page load time improves from 8 to 2 seconds.

Speed doesn't mean ugly

And if you think that speed means an ugly design, think again. There are heaps of templates and libraries (like jQuery) that give you great smartphone design patterns and elements to make your site slick, fast and app-like.

Test for speed

Force everyone involved to test your website on smartphones with the Wi-Fi turned off. Get them to try it when travelling or in places with poor signal reception. Give your developers some of the nice resources in this section and send them to mobile conferences regularly.

Just try harder to get a balance between good design and something that loads before my train journey is over!

Use a Content Distribution Network (CDN)

If you‟re operating internationally, I‟d advise using a Content Distribution Network (CDN) like Akamai, Level 3 etc. These content networks can speed up site load time by caching your site or data at a city level for your mobile users to get fast response. Every millisecond counts.

I‟d like to see more work here from big retail brands and popular sites, to get the size of their mobile websites optimised and trimmed. I regularly see pages where you‟re downloading 30 or 40 items and pages of 100 or more Kilobytes, which can turn into 1-2 minutes of download time. Yawn.

Avoid redirection

The other problem I see often is where a visitor is bounced around when they visit a site. You start by loading, which then takes ages to redirect to, which then redirects to the mobile website,

This is really slow for the customer and it sucks money, as well as experience. It's called redirection and it happens when the technical people haven‟t done it a better way.

Every mobile device shouldn't be tossed around like a salad. Take them directly to their experience.

Of course, if you have a fast and solid 3G connection everywhere you go, the performance hit becomes less important. But the idea of the 'always on everywhere' fast connection stuff, it's simply not a reality yet, so stop making people wait ages to use your pages.


Slow page performance makes for a lousy mobile experience and poor sales. If companies let this happen through inaction, they‟re harming their own business through lack of respect for the customer.

Some of these people may also be heard saying "Hey, this mobile thing is never taking off – we never sell anything anyway. Ha ha ha!" How ironically put, as the opportunity then gets siphoned off by the competition!

There is a huge amount of data to show that every millisecond in page load time on your site makes a noticeable difference to your conversion or engagement. Mobile is where this becomes critically important for success. The attention span and patience of a mobile user is equivalent to a Peruvian gnat that‟s been at the white powder.

This isn‟t a geek thing – this desire and design for speed – it‟s a business thing, a conversion thing and a competitive advantage. Take it.

Graham Charlton

Published 29 February, 2012 by Graham Charlton

Graham Charlton is editor in chief at SaleCycle, and former editor at Econsultancy. Follow him on Twitter or connect via Linkedin.

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Comments (5)

Andrew Stockwell

Andrew Stockwell, Head of Account Management at RedEye InternationalEnterprise

Excellent set of points and statistic in here Graham. From the mobile UX research that we have done here at RedEye when looking at users who regularly purchase (at least one item a month) on a portable device the number who would abandon due to slow load would be even higher. I have seen many examples of regular mobile users abandoning a brand entirely if they can't easily use the mobile site. See RedEye's introduction to mobile marketing here:

over 6 years ago

Graham Charlton

Graham Charlton, Editor in Chief at SaleCycle

Thanks Andrew

over 6 years ago



"This is really slow for the customer and it sucks money, as well as experience. It's called redirection and it happens when the technical people haven‟t done it a better way.

Every mobile device shouldn't be tossed around like a salad. Take them directly to their experience."

When you say "take them directly to their experience," what are you hoping happens? It sounds like you're saying mobile should have a different experience ("Why should they be big, like a desktop site? Can‟t they be smaller and faster?") but I'm not sure how you plan to get that person there without some sort of redirection whether it's at the client or server level.

over 6 years ago

Matt Clarke

Matt Clarke, Ecommerce Director at B2B

A few years ago dotMobi produced a very useful online testing tool called mobiReady which allowed you to test your mobile site for compliance to dotMobi standards and see how it would render on the then popular devices of the time, such as the Nokia N70.

While the device visualisations (and perhaps some of the recommendations) have dated, the mobiReady service remains, I think, quite useful for getting an indication of what extra steps can be made to get mobile sites running a bit quicker. If you can get your mobile site to score well in mobiReady then it will certainly be nippy. Compression (Gzip) and image compression are also worth looking at to get some extra speed out of mobile sites if you're re-rendering desktop content.

over 6 years ago

Matt Clarke

Matt Clarke, Ecommerce Director at B2B

Another really useful tool for optimising mobile site is Google Page Speed Online, which now includes an element for mobile sites. If you pass it your URL it will even follow redirects to a mobile site based on user agent, allowing you to get a good idea of how well (and how quickly) it will render for visitors.

over 6 years ago

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