The average load time for mobile sites is 19 seconds when running on 3G connections, which Google says is "about as long as it takes to sing the entire alphabet song."
Some 77% of mobile sites take longer than 10 seconds to load when running on 3G networks. On 4G networks the average time isn't much better at 14 seconds, per Google.
Google's latest study — The Need for Mobile Speed — found 53% of mobile site visits are abandoned if pages take longer than 3 seconds to load. One out of two people expect a page to load in less than 2 seconds. The data is based on analysis of more than 10,000 mobile Web domains.
Sites that load in 5 seconds versus 19 seconds observed 25% higher ad viewability, 70% longer average sessions, and 35% lower bounce rates.
The study also analyzes the relationship between page speed and revenue. While there are several factors that impact revenue, the model projects that publishers whose mobile sites load in 5 seconds earn up to 2 times more mobile ad revenue than those whose sites load in 19 seconds.
Google says that file size, ads, images, videos and measurement technology slow Web site load times, providing the following stats:
The average mobile Web page is 2.5MB in size, which means the data alone takes 13 seconds to download on a fast 3G network. The average size of ads is 816KB, which takes 4 seconds to load over a 3G connection. And 1.49MB is the average size of content, which takes seven seconds to load over the same speed network.
Speeding up the Web requires more than Google's Accelerated Mobile Pages (AMP) project, according to the execs at Marfeel, an ad-tech platform that is changing the way publishers create mobile Web sites. The company's product is compatible with AMP. It has been serving customers content via HTTP/2 to more than 1 billion visits worldwide and claims the publishers it works with serves content on their sites in less than 0.8 seconds.