How much does site speed impact SEO performance?

How fast a website loads is a crucial SEO consideration for every online business but is often completely ignored. 

This is surprising given that a bad user experience is bad for business.

Page speed has a direct impact on conversion rate according to a number of studies, in one of which Walmart experienced 1% growth in revenue for every 100ms of improvement.

From an SEO perspective, Google are all about offering the best onsite experience possible and have explicitly told us that site speed is a ranking factor.

Search engines understandably do not want slow websites appearing high up in their results pages.

“Speed as a factor has reportedly been part of the algorithm for a good 5+ years now, and this makes sense”, says SEO expert Oliver Mason. “More people than ever browse on mobile devices with limited bandwidth and processing power. Google wants to satisfy its users, and slower sites do not increase user satisfaction.”

A slower site will actually cause problems for the Google crawler. Tom Clark of Convert Digital adds that "aside the obvious issue of potential visitors clicking back when the site is loading too slow, Google bots will have a shorter time to crawl pages and therefore will not index your content as frequently”.

What is the actual impact on rankings?

Whilst it’s clear that site speed has an impact on SEO performance, what’s less certain is how much of an impact it has.

According to SEMrush, the actual impact on rankings is in most cases minimal.  A blog post written at the end of 2015 claims that “while Google seems to reward fast-ranking websites, it won’t hurt your rankings drastically, unless your website is very slow.”

In fact, Google stated in 2012 that only 1% of search engine results actually get penalised by the page speed factor.

However, a recent study in 2016 analysing the median load time of 1 million domains found that pages on fast-loading sites rank significantly higher than pages on slow-loading sites.

The results clearly show that sites ranking in the top position have on average the fastest sites, with a load time of less than 2 seconds.

“So, to rank in position 1 my site needs to load in under 2 seconds?” I hear you ask. Well, sort of.

This is just a correlation, and the site owners who optimise for speed probably optimise for SEO as well, so take the graph with a pinch of salt.

Oliver Mason explains that “the impact of site speed on ranking's isn't something many have attempted to quantify”. All things being equal, the faster site will rank better. Unfortunately all things being equal never happens outside of very artificial SEO tests”.

It seems that no study therefore will ever be able to say with certainty that improving your site’s speed by x amount of milliseconds will improve your average position by y. However, site speed will always be an important ranking factor and could mean the all important edge in organic position over your competitor.    

If you want to improve the SEO performance of your website, please get in touch.