Page speed has been a ranking factor for a couple of years now. What's more, each year, its importance to your site's SERP positions is only growing higher.

What started as another metric to determine how quickly a person will see the content they've requested has turned into a massive indicator of the site's overall user experience. 

Pages that load faster deliver content quicker, and in that, satisfy the user's needs quicker. 

On this page, you'll learn about the following:

What is Page Speed?

Page speed is defined as the length of time it takes to display all the content on a specific page or the length of time it takes for a browser to receive a web server’s first byte (or, to put it in less technical terms,  page speed is how long it takes for the browser to receive the first batch of information from the server).

Every page element - its HTML code, CSS that styles page elements, various JavaScript files, images, videos and other multimedia and so much more - affects the page speed. In fact, anything from an element's size (measured in kilobytes) to the speed of the web server they are hosted on will affect the page speed. 

Page speed is measured on desktop and mobile devices separately. This is because of technology differences between the two, resulting in a different experience for desktop and mobile users. 

Page Speed vs. Site Speed

Though they may seem similar, page speed is not the same as site speed. Site speed is the average of several sample pages on a website. Page speed, on the other hand, describes how long a person will wait to start consuming an individual page. 

Why Page Speed Matters

Page speed is important to users because, well, faster pages are more efficient and provide a much better on-page user experience.

Per a recent Kissmetrics infographic, if a page takes longer than 3 seconds to load, over a quarter of users will click away.

Mobile users expect speed, too. In the same survey, 73% of users reported visiting a website that loaded too slow. Page speed also affects conversion rate. For example, noted that with every second of increased page speed, they saw a two percent increase in conversion.

But, perhaps less intuitively, page speed is also important for search engine optimization (SEO).

In 2010, Google announced that page speed would be included as one of the ranking factors for their search index.

In 2017, Google announced they will give page speed even more consideration, incorporating mobile site speed to rank sites on its “mobile-first” pages, or pages that individualize rankings for mobile sites. Google is also experimenting with an Accelerated Mobile Pages Project (AMP) – a project aiming to make pages load more quickly on mobile devices.

And this year, the search engine expanded the importance of the user experience by introducing Page Experience to its ranking signals. 

Page experience signals aim to evaluate web pages by the quality of their user experience for real people. In short, they expand Google's recent on-page criteria with factors that affect the person's experience while consuming the content. 

Needless to say, page speed is one of the most critical factors that affect it. 

Page Speed Metrics

Page speed is a complex factor, and to overcome any issues relating to it, it pays off to understand how it is being measured. 

There are several metrics that affect or relate to page speed:

  • Load time which defines how long does it take for an entire page to display in a browser's window. Worth to note that for that to happen, all file and script must be loaded and all HTTP requests have to be fulfilled. 
  • Page size defining the total size of all resources a page comprises of. These resources include all code elements, scripts, images, and other files. 
  • Time to First Byte (TTFB) measures the time between a browser requesting the page and the first byte of the information is returned by the server. 
  • Round Trip Time (RTT) describes the time it takes for the complete request for information - from the moment the browser makes the request, to the time it takes to reach the server, and how long it takes for the response to return to the browser. 

Factors that Slow Pages Down

With these persuasive statistics, you certainly want to make sure your site is loading quickly. Take into consideration a few ways your site might slow down.

First, a heavy image page, especially on sites with responsive or high DPI images, can load slowly. Optimizing images can make your website more lightweight; so can distributing them through a content delivery network (CDN) to render those files from location closer to where the user is.

Another problem occurs if your web page has too many large files that must be downloaded.

Rendering too many JavaScript scripts will slow a page down as well. A JavaScript compression or minimization tool decreases your download size.

Unused code, be it CSS, JS or other scripts left over in the page's HTML will also increase the page load time. 

Another severe problem is rendering scripts too early or too late. Often, webmasters design their pages to be consumed only after the entire content has been loaded. However, for most users, seeing the above the fold content first is enough to start enjoying the page. This gives the browser time to load the rest of the page (all below the fold elements,) without keeping a user waiting. 

Analyzing Page Speed

You might not know how users are interacting with your website if you don’t analyze page speed. Google’s PageSpeed Insights lets you see your pages’ load speed score, in addition to giving you the reasons – listed above – that your page may not be loading as quickly as it could be.

google page speed insights


However, the averages provided by these Google tools do not always paint a complete picture. A quick look within seoClarity PageSpeed provides useful insights as you make the changes that Google's PageSpeed insights suggests. You can do before and after analysis and also correlate the changes to see if that resulted in an increase in traffic and conversion on your site.

PageSpeed_1Another view from seoClarity that shows the overall results from all Page Experience metrics. Use seoClarity to sort by issues affected the greatest number of pages or recognize which pages or page types have the most issues or resolved issues month over month. 


As we look forward, though, one thing is clear: optimizing your page speed is necessary for the future. As Google continues to reward mobile-friendly and sites with your SEO focus should be on improving your page speed.

Editor's Note: The SEO industry changes fast! This post was originally published in January 2017 and has been updated for accuracy.