Page load time is a critical aspect of web development for several reasons. Slower page load time results in page abandonment and lower conversion rates. When someone arrives at your website and it takes too long to load, they leave, but many of them will tell their friends about their experience. This also means people won’t be buying the products you offer for sale on your site. These results are definitely not the desirable results.

Page Load Time and Large Websites

Companies with large websites including Amazon have conducted studies showing that users demand a page to load quickly, and in fact slower page load times lead to a significant drop in revenue – some estimates say up to 1% loss for every 100ms delay in page load time. Leading ecommerce beauty site Adore Beauty found that faster pages resulted in a 16.5% increase in conversion rate and a consistent improvement in revenue.

Translating these studies from high-volume websites like Google and Amazon to the many thousands of small and mid-size websites out there can be difficult. Some may argue that page speed matters more for giant websites who are expected to perform well even under high traffic, while other studies have found it hard to measure the impact of page load time across thousands of websites.

Measuring the Impact of Page Load time

It is difficult for websites to measure the impact of page speed on user experience themselves. Google Analytics takes a very basic measure of website speed as experienced by your visitors – they show overall page load time for a sample of 1% of visitors. For many websites the Google Analytics sample size would be extremely small and therefore skewed by the different connections of the end-users being sampled. This won’t be an accurate measure. More advanced tools like New Relic measure the various elements of page load time – including back end time, front end time, and total page load time – but do not link this data to marketing metrics like page views per session and bounce rate.

Additionally, many of the often-cited page speed metrics are from several years ago, when end-users had different connection speeds (especially on mobile devices) and expectations around how fast pages should load. Today many users expect even faster page load times, and with the growth of ecommerce-only retail businesses and internet-only media companies, page speed has more of an impact than ever.

Page Load Time Affects Revenue

What does all of this mean for your website? From these studies we can see that page load time does impact both number of pages viewed per session and the bounce rate. As any marketer knows, these are important metrics that can have a direct impact on conversion rate and revenue. These issues need to be addressed by all website owners.

Pages viewed are important because they show a visitor is engaged with your website and is staying on the site through several page loads. For ecommerce sites, more pages viewed generally means a higher likelihood that a visitor will add one or more items on a page to their cart. It also could mean larger cart sizes. As we have found previously in A/B tests, faster pages equal larger carts and more revenue.

Page Load Time Metric

Pages viewed per session are also a crucial metric for media sites and other websites which rely on page views for advertising revenue. The cost and effort of acquiring a new visitor to your website is often high, so once they are on your site you want to make sure they will stay and view several pages to get a strong return on investment. The faster the pages load time, the more likely they will view more pages and become a valuable visitor in terms of both advertising and the likelihood they will return to your website.

Bounce rate is the percentage of visitors who come to your site and leave after only viewing one page. This metric can be impacted by many factors, including page content, page design, and how relevant your page content is to the search term or advertisement that brought visitors to your website. Page speed also impacts bounce rate, and because those who bounce only visit one page on your website, the load time of that first page is extremely important. If a visitor has never come to your website before, they will need to collect all assets from your web server or cache server. A very slow time to first byte or start render time could mean visitors leave your website before the first page has even loaded.

The Verdict: Page Load Time Matters

The data in demonstrates that page load time does have a clear effect on both bounce rate and number of pages viewed, but it’s important to remember that every website is different, and content, design, and overall user experience will also impact these metrics. You should use one of the many available tools to measure page load time on your site. Once you have tested your site you will want to fix the issues causing the slow page load time. One tool I really like is at http://webpagetest.org. It allows you to select a location from a map where a simulated visitor is coming from and then it tests page load time for the website you enter.