Page load time

Blog tutorial Page load time

What is page load time ?

Typing the address of a website or clicking a link in the browser sends a signal to the server that we want to download the website. Afterwards, the server responds and the website is sent to the user’s browser. This rather complicated process of server communication runs in the background and is not visible to most users. The complexity of page loading can cause delays on many stages[2]. We have very limited control over some of those delays (like poor phone reception) but greater over others (e.g. website structure).


IS IT GOOD TO HAVE FAST PAGES?

An average mobile page load time in 2016 was 22 seconds[1]. The year after it was 15 seconds[3]. The progress is significant but there is still room for improvement. Google research shows that more than a half of mobile users (53% to be exact) abandon a site if it loads for longer than 3 seconds. Speeding the site up by just 0,1s results in increased income.

Page load time has been impacting search engine rankings since 2010[4]. Since July 2018[5], it has also been a factor in mobile search engine rankings.

Page load time is extremely important in the case of complex websites. Search engines have specific resources (crawl budget) to use while indexing websites. Slow websites cannot be indexed fast, which impacts their visibility in search engines.

Long page load time impacts conversion (intended actions on the website like making a purchase, filling contact form). The longer the page loads, the fewer people are able to convert[7].


HOW TO MEASURE PAGE SPEED?

Loading speed can be divided into two parts:

  • server response time - time-to-first-byte (TTFB) - time to acquire the first data byte by a browser
  • page load time - time required to download the page content (without CSS, JavaScript, Images)


(https://moz.com/blog/how-website-speed-actually-impacts-search-ranking, 2013)[6]

Research done in 2013 showed the dominance of fast loading websites (short TTFB) over the slower ones. Fast pages ranked higher.


HOW TO SPEED THE PAGE UP

  1. turn on file compression
  2. reduce the size of CSS, JS files 
  3. reduce the size of images - they often take lots of space. If the connection speed is fast, big images do not matter. However, many users connect via slower wireless devices. Keeping those users in mind, reducing the size of images is recommended.
  4. limit the number of redirects - every redirect is another batch of data sent between browser and server. The smallest number of redirects possible is recommended.
  5. make use of asynchronous scripts - it is usually enough to add async attribute.

    <script async src="http://code.jquery.com/jquery-1.11.1.min.js"></script> - asynchronous loading of a script

  6. make use of a browser’s cache - you can limit the re-downloading of resources from the server. 
  7. reduce server response time - response time above 0,2 seconds is alarming. Reducing response time often requires changing a hosting company. However, since slow server means fewer customers, it is a good option to consider. 


    (very long server response time, Google recommends less than 200ms)
  8. In the case of Wordpress CMS based sites use a plugin that speeds the pages up with cache e.g. W3 cache.
  9. avoid importing CSS files from other CSS files


Server resources

A correctly created and fast website is just one of the steps to being successful. Having backup server resources to handle extra traffic is strongly recommended. A backlink on a popular website can generate up to a couple thousands of visitors in one day. A public TV mention might generate even more. There aren’t many companies that can afford to lose 100 thousand of visitors - a traffic worth tens of thousands of dollars.


DIFFERENCES IN PAGE LOAD TIME

In some cases page load times might vary greatly. That can be caused by server overload or cache filling. When a server is overloaded, page load time is longer which lowers the user experience and increases the number of visitors abandoning the site. For that reason, it is important to store a website on a stable hosting with a decent amount of backup server resources and the ability to handle traffic even in rush hours.

If the first page load time is longer than the subsequent load time, it might indicate that the cache expires often and the majority of users generate pages instead of loading them from the cache, which is much faster. Cache works on multiple levels - not only the website itself can be cached (there are plugins for CMS like Wordpress) but also website files located on the hard drive or databases used for system generation.

To illustrate the difference, let's use an example. Generating a big and complicated website may take 500-3000ms. Loading the same website from cache on a hard drive will take only 100-300ms. The more users load pages from cache, the better their user experience is. Speeding the pages up is also advantageous for search engine robots. If a website is fast, scanning robots visit it more often and evaluate its performance better. Search engines’ algorithms assess the quality of the website and the amount of resources they need to scan it. The faster the website is, the less resources are needed and the robots will visit it more often.


CONCLUSION

Page speed is crucial for user experience. Google evaluates page speed to determine the ranking of a website. Making sure the page load time is as short as possible is highly recommended.


Sources:

  1. https://www.thinkwithgoogle.com/marketing-resources/data-measurement/mobile-page-speed-new-industry-benchmarks/
  2. https://sachsmarketinggroup.com/factors-that-affect-website-speed/
  3. https://www.thinkwithgoogle.com/_qs/documents/57/mobile-page-speed-new-industry-benchmarks.pdf
  4. https://webmasters.googleblog.com/2010/04/using-site-speed-in-web-search-ranking.html
  5. https://webmasters.googleblog.com/2018/01/using-page-speed-in-mobile-search.html
  6. https://www.icrossing.com/uk/ideas/slow-pages-lose-users
  7. https://www.globaldots.com/how-website-speed-affects-conversion-rates/
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