Seconds do matter. In fact, the probability of a mobile site visitor bouncing from a page more than doubles when the page load time goes from 1 second to 10 seconds, according to Google’s updated look at mobile page speeds. The good news? Average page load speeds have improved from last year. The bad news? They’re still not fast enough.
Indeed, 70% of the landing pages analyzed took more than 5 seconds to display the visual content above the fold, and it took more than 7 seconds on average to fully load all of the visual content both above and below the fold.
To arrive at its conclusions, Google analyzed 11 million mobile ads’ landing pages across 213 countries. The rest of this article discusses page data for the US.
Page Load Speeds
So which categories have the slowest page loads?
As it stands, Technology has the dubious distinction of leading the pack, averaging 6.7 seconds to display page content to users. While that’s more than twice as long as the best practice time of 3 seconds or less, it is a big improvement from last year’s 11.3-second average.
CPG comes in right behind at 6.6 seconds, followed by Automotive (6.3 seconds) and Retail (also 6.3 seconds). The vertical with the quickest average tested speed across sites, coming in with the lowest time of 5.4 seconds, was Healthcare, with Media & Entertainment hot on its heels (5.5 seconds).
Average Time to First Byte
There are various factors that play into mobile page load speeds, and the responsiveness of a mobile web server is one such element.
But while the speed and responsiveness of the web server does have a role, the data reveals that the servers might not have as much to do with mobile’s overall sluggish load times as other elements.
The industry with the slowest web server was Finance, which averaged 2.3 seconds to first byte. Even that wasn’t too far from the optimal 1.3 seconds or less, however.
In fact, two categories approached the best practice recommendation: Automotive, which enjoyed the fastest speed, clocking in at 1.5 seconds; and Automotive, next at 1.6 seconds.
Average Request Count
The average request count refers to the number of individual pieces of content needed to display the entire mobile page. In this case, a lower number is preferable, as Google has found in the past that the probability of conversion on a page plummets by 95% when jumping from 400 to 6,000 elements.
Mobile pages should, according to Google, have fewer than 50 pieces of content needed to display the entire page. The industry that has the highest average request count is Automotive with a whopping 153, followed by Retail with 147 and Technology with 140. It appears that this is a significant factor, as those three industries had the slowest page load speeds overall.
Meanwhile, even those on the lower end of the spectrum – Finance (90), Healthcare (98) and Media & Entertainment (110) – are still well above the best practices recommendation.
A review of last year’s benchmarks indicates that the average number of requests seems to be trending in the wrong direction.
Average Page Weight
Another way of measuring page size is by weight. And here’s an area where size matters – and smaller is better. While the best practice is to keep mobile pages under 500KB (half a MB), 79% of the pages measured globally weighted more than 1MB, and a majority (53%) weighed more than 2MB. On a somewhat encouraging note, simple compression is a good first step: one-quarter of the pages analyzed could save more than 250KB just by compressing images and text.
Within the US, the Automotive (3.8MB) vertical had the highest average page weights. At almost 8 times the best practice recommendation, these “heavy” pages are likely the result of the high request counts mentioned above.
Close behind, the average weight for CPG pages was 3.7MB, with Retail also close behind (3.6MB). Once again, average page weights appear to be increasing rather than decreasing: last year none of the verticals analyzed averaged more than 2.3MB. This year, only one came in below 2.3MB: Finance, at 2.0MB.
The full benchmarks can be viewed here.
About the Data: Google Research and Webpagetest.org sampled 11 million global mobile web domains loaded using a globally representative 4G connection during January 2018.