Search Engine Optimisation

Does Site Speed Help SEO?

The performance of your website dramatically influences search rankings.

We recently published that Google had confirmed site speed as a mobile ranking factor. With this update, named the “speed update“, now taking place this month, we felt that it was a topic we should revisit in more detail.

Google first announced site speed as an SEO ranking factor back in 2010. This was primarily aimed at desktop sites and encouraged web designers to address performance issues that would slow down sites. In the article, Google shared several website speed testing resources that would help web design teams identify performance problems. Site speed was explicitly named as a ranking signal and has been considered a crucial SEO factor ever since.

At the start of 2018, Google announced that page speed would be a ranking factor in its mobile-first index. The “speed update” was detailed to be rolling out in July 2018 and would affect a small, undisclosed percentage of queries and focus on pages that delivered the slowest experience to users. While this may seem unimportant for the vast number of sites, do not forget the original speed ranking signal remains in effect, and there’s certainly scope for Google to cast a wider net in future.

Research shared by Google indicates that site speed has a significant effect on user behaviour and faster sites perform a lot better. The information shared shows that bounce rate increases by 32% when the page load time goes up from 1s to 3s. Incrementally, 1s to 5s increases bounce rate to 90%, and if a website site takes 10s to load, the chance of a bounce increases to 123%. These are some pretty compelling figures, especially when, according to Google, the average page load time for a mobile landing page is 22 seconds.

So how does site speed help SEO?


These user behaviour metrics are what Google uses to determine the importance of site speed for user experience. Google want to recommend the best websites as this is its core purpose as a search engine. From what we can see above, speed plays a crucial role in users accessing and staying on a site. Therefore, Google will measure site speed when crawling your website and use this score to determine rankings. The importance of site speed for user experience increases the weighting of this aspect as a ranking signal.

Furthermore, Google has developed new methods to gauge user experience that should now be part of a modern SEO strategy. RankBrain looks for when users click on a page and stay there, measuring click-through rate and dwell time. If users are bouncing back to search results because of slow page speed, this will negatively affect SEO.

Speed is a battleground where professional sites have an opportunity to stand out. As the mobile-first index comes into effect, we’re confident that speed will play an even more prominent role, considering slower connection speeds over 3G and 4G devices. Responsive design must address how assets are loaded across different devices to ensure optimal page load times.

If you are concerned about your website speed and how this plays a part in your SEO strategy, please contact our team.

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