Back in 2010, Google announced that webpage loading time was officially a factor in a their search algorithm.
Page load speed is important because with that every additional second a webpage takes to load, the likelier a user will give up on that page. Multiple tests confirm that load times negatively impacts user engagement, CTR, conversions, and time on page.
Essentially, if it impacts a user’s experience, then it will affect your SEO visibility. For years, Google has always asserted “What’s good for the user is good for SEO” and has made small tweaks and major overhauls to their algorithm based on this simple principle.
From Google’s SEO Guide:
Even though this guide’s title contains the words “search engine”, we’d like to say that you should base your optimization decisions first and foremost on what’s best for the visitors of your site.
Google has also done internal tests by slowing down their own search results to measure the impact on user behavior. In a blog post titled “Speed Matters”, the results of their experient found that milliseconds mattered in terms of page engagement:
Our experiments demonstrate that slowing down the search results page by 100 to 400 milliseconds has a measurable impact on the number of searches per user of -0.2% to -0.6% (averaged over four or six weeks depending on the experiment). That’s 0.2% to 0.6% fewer searches for changes under half a second!
But what is the recommended page load speed for optimal SEO? There are multiple sources across the web that mentions Google recommending webpages should load in less then 2 seconds (most citing this ClickZ article), but I struggle to find where Google officially mentions this.