January 31, 2019 | by Jon Fletcher

What below-average mobile speed costs websites

16 statistics that prove the value of mobile speed for digital publishers


Every digital publisher knows that speed is crucial to their site. It is the first impression of your website and an indication of the quality of your content. But, what constitutes a fast mobile site — for your users, and for Google— and what does having a below average site cost you?

Let’s start with the key statistics:


47% of people expect your site to load in less than two seconds

53% will abandon it entirely if it takes longer than three seconds

Already, you can lose half your traffic before you display any content. Regardless of the quality your output, mobile speed is deeply ingrained into the success of your website. It is merciless.

An additional one second delay—total of three seconds of waiting— decreases customer satisfaction by 16%

For users, a page load time of two seconds seems to be an acceptable threshold. Above two seconds, web pages will start to experience negative effects due to their page speed.

In January 2018, Google conducted research using 11 million global mWeb domains using a globally representative 4G connection. They were able to gather empirical data regarding how users react to various mobile speeds.

In addition to the loading time, they tested how the speed of the site affects the success of the page. They discovered that:

If the page load time increases from one second to 10 seconds, the probability of a mobile site visitor bouncing increases 123%

In addition to direct loading times, slow mobile websites are generally heavy with elements. This slows down the performance and affects the conversion rate.

If the number of elements—text, titles, images—on a page goes from 400 to 6,000, the probability of conversion drops 95%

52% of online shoppers state that quick page loading is important to their site loyalty

Let’s put this into more tangible terms.

If Amazon had a 1 second lag on their site, it would cost them $1.6 billion in sales each year

A slow down of Google of just 0.4 seconds would lose them 8 million searches per day

The point is abundantly clear. Have a slow site and it will cost you severely. However, making improvements is possible. Many of these areas can be optimized to increase speed.

Let’s look at the page weight for a start:

25% of pages could save over 250KB by compressing images and text

10% can save more than 1MB by compressing images and text

But, there is no sense in optimizing unless you know the speed you need to achieve to improve your bottom line. Fortunately, Google makes no secret of the benchmarks they expect websites to hit in regard to speed.

Average speed index – Under 3 seconds
Average time to first byte – Under 1.3 seconds
Average request count – Fewer than 50
Average page weight bytes – Less than 500kb

Whilst they are unwilling to explain the exact weighting, it has been public knowledge since 2010 that Google uses page speed as a ranking factor. It can be safely assumed that not meeting these benchmarks will have negative repercussions on your site ranking.

Finally, we can look at the example of Walmart, who recently published the results of their own investigation into the effect of site speed. This example demonstrates the benefits of going from slow to fast.

And Walmart was slow. For the slowest 5% of users, an item page would take around 24 seconds to load. Their goal was to increase page loading speed to under 20 seconds for 95% of their users.

The main motivation behind this was a sharp dive in the conversion rate, directly correlated with an increase in page loading time.

Walmart Speed stats

By reducing excess page elements, slow third-party scripts, multiple hosts, and implementing various best practices, Walmart were able to hit their target. This showed unmistakeable, dramatic value, coming directly from the increase they generated from increasing the site speed.

For every 1 second of improvement they experienced up to a 2% increase in conversions

For every 100 ms of improvement, they grew incremental revenue by up to 1%

The statistics are blunt. Site speed directly affects the value of your website. Increasing speed will increase user satisfaction and core metrics such as page views, leading to higher advertising revenue.

Marfeel is Google Certified Partner and creates Progressive Web Apps that are designed to load in under a second. Learn more here.

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