Yesterday I mentioned that Google does take page loading speed into account when ranking sites (and in determining how much of a site it will crawl). As Google is switching to only crawl sites as a mobile browser, that means it’s more useful than ever to have a fast response on the mobile display of your website.
As far back as ten years ago, research suggested that a two-second response time was about all people would accept before some fell away. More recently, a whole post on the subject from Google in 2018 said that as page load time goes from 1 second to 6 seconds, the probability of bouncing increases by over 100%. Yet “For 70% of the mobile landing pages we analyzed, it took more than five seconds for the visual content above the fold to display on the screen, and it took more than seven seconds to fully load all visual content above and below the fold.”
I just tested out a dozen or so sites from clients of ours (typical engineering and scientific companies) over 4G, and found it was typically about 5 seconds before there was something to read, but nearer 10 seconds before the site seemed to have completely loaded. With the sites I run, one of the targets I have is to get the speed index score at Google’s PageSpeed Insights into the green (about 4 seconds). If you’re interested in actual numbers, there’s more to read on the subject in The state of page speed in 2020: statistics publishers need to know on the Ezoic blog.
Does it make any difference to Google rankings? Tests I’ve seen online have varied results, but it’s likely to make more of a difference when you’re lower down and small changes have greater impact. As with many aspects of SEO though, don’t forget that what you’re doing for the real website visitor is the main thing, and a faster site is always better for them.