Site Speed is (Still) Impacting Your Conversion Rate


Updated on August 20th, 2019, to include current data and insights.

It’s common knowledge that site speed impacts the user experience on your website. But how, exactly, and by how much? Does a slower website literally mean lost dollars?

Absolutely. There have been multiple studies, including Portent internal research, which have concluded that site speed impacts both conversion rate and sales.

Portent’s Director of Analytics, Michael Wiegand, and I did some analysis based on e-commerce and conversion data from 10 websites and over 26,000 landing pages worth of data.

Research Method

For value/page view data, we looked at just over 94 million page views across 10 e-commerce sites. The critical statistics:

  • We took a 30-day snapshot
  • Sessions per website varied from 39,000 to 718,000 and higher
  • Three of the sites were B2B e-commerce. The rest were B2C
  • The sites ranged from major national fashion brands to small, niche manufacturers

What We Found

These are our findings when comparing site speed versus conversion rates:

  • 0-4 second load time is best for conversion rates
  • The first 5 seconds of page load time have the highest impact on conversion rates
  • Website conversion rates drop by an average of 4.42% with each additional second of load time (between seconds 0-5)
  • Website conversion rates drop by an average of 2.11% with each additional second of load time (between seconds 0-9)

The following is the breakdown of our results, and how you can capitalize on opportunities.

Site Speed has Increased Across All Sites and Industries

Our study showed that 78% of website pages have a load time of 5 seconds or less, and 22% have a load time of 5 seconds or more. Comparatively, when we last ran this study in 2014, 50% of the sites had an average load time of 5+ seconds. More than double the number of websites in the 5+ second page load time have increased their site speed and reduced load time. As overall site speed increases, website users will have a continued expectation of faster loading times.

To Improve Goal Conversions on Your Website: Aim for a 0-4 Second Load Time

User behavior goal conversions on websites are generally achieved at a higher rate than e-commerce conversions on websites. Web behavior conversions have a lower barrier to complete than transactions.

However, while overall goal conversion rates are higher than transaction rates, the dropoff of conversions is much steeper. When pages load in less than 1 second, the average conversion rate is almost 32%. At a 1-second load time, the conversion rate already drops to 20%. At 2 seconds, the conversion rate begins to level off at 12-13% and reaches it’s lowest at a 5-second load time.

Screenshot of goal conversion rates from sites studiedScreenshot of goal conversion rates from sites studied

Following the 5-second page load time, there is a return to a +10% conversion rate for subsequent page load times. However, the dropoff has already lost time and potential user conversions. And the biggest improvements in conversion rates are to be captured when the site loads between 0 and 2 seconds.

To Improve Transaction Conversions: Aim for a 0-2 Second Load Time

Zero to 2 seconds sounds astonishingly fast. But when website users are accustomed to fast load time across the web, slower sites are penalized when visitors abandon the site visit in favor of a faster website to make a transaction.

The highest e-commerce conversion rates occur between 0 and 2 seconds, spanning an average of 8.11% e-commerce conversion rate at less than 1 second, down to a 2.20% e-commerce conversion rate at a 5 second load time. After that, conversion rates are largely below 2% (except for the 7-second anomaly, which briefly returns to 2.11%).

Between seconds 0 and 5, the e-commerce conversion rate decreases by an average of 1.2% for every additional second it takes for your website to load. But we see a consistent correlation between faster loading pages and higher instances of e-commerce conversions.

Screenshot of transaction conversion rates of sites studiedScreenshot of transaction conversion rates of sites studied

Quick math to further demonstrate this point:

If 100 people visit your website for a $50 product, this could illustrate the difference in your potential earnings:

  • A <1 second page load time at an 8.11% conversion rate results in $405.50
  • A 1 second page load time at a 6.32% conversion rate results in $316.00
  • A 2 second page load time at a 4.64% conversion rate results in $232.00
  • A 3 second page load time at a 2.93% conversion rate results in $146.50

In the span of ~4 seconds, potential sales have dropped by just over $250. Multiply that across more visitors to the websites, and potentially higher-priced products and services, and that results in significant gaps in potential revenue.

Some Pages Matter More Than Others

Hardly news, but faster checkout, login, and home pages matter most. After that, load speed for product category pages have the most impact on sales. All of these pages have high consumer-intent traffic. Make them fast.

How Can I Improve My Site Speed? Factors to Consider

Page ‘weight’ (that’s the total kilobytes transferred, images and all) is no longer the biggest factor in site load time.

The reason? Many sites have streamlined their code, learned to “minify” their code and to use GZIP compression. So the bigger factor, in many cases, is the server and page configuration.

If you want to speed up your site, look at the following elements.

JavaScript Timing

Where possible, put JavaScript src ‘.js’ includes at the very end of your page, defer them, or load them asynchronously. For example, if you use Google Analytics or jQuery, you’re including these scripts in your page from external files. These are ‘blocking’ calls, and your page may not appear to the user until these scripts fully load. If something goes wrong, or the script just takes a few seconds, the perceived delay can kill conversion rates.

Use deferred execution if you need to fire the javascript after the entire page loads.

Use asynchronous execution if you don’t care when the script fires.

Resident Portent SEO expert Evan Hall also recommends configuring non-essential Google Tag Manager tags to fire on “DOM ready” or “Window Loaded” to improve page speed. If a GTM tag isn’t critical to rendering a page, see if you can fire it a little later.

Screenshot of DOM Ready and Window Loaded trigger options in GTMScreenshot of DOM Ready and Window Loaded trigger options in GTM

ETags and Expires Headers

Other page speed factors are ETags and expires headers. These may sound scary, but expires headers, in particular, are easy to set. Your IT team or web host will know what to do.

These two settings help reduce the number of requests a browser makes to the server. They tell visiting web browsers which files to update. If set correctly, you can prevent those browsers from reloading files that rarely change, such as your logo. This is useful for websites with recurring visitors, who do not need to load the page from scratch every time.

Browsers will cache files with far-future expires headers and keep it cached, so the apparent load time is far shorter. And they’ll use ETags to more easily check if a file has changed.

Image Size

Page weight may not matter as much. But image size is still a major drag on load times. Please, compress images.

Run Google PageSpeed Insights on your site. There is a section in this report that provides feedback regarding proper sizing, lazy loading, encoding images, and recommended image format.

Screenshot of Google Pagespeed Insight results for Portent.comScreenshot of Google Pagespeed Insight results for
Image Results for
Screenshot of Google Pagespeed Insights recommendations for Portent.comScreenshot of Google Pagespeed Insights recommendations for
Additional considerations for optimizing images for a website

Then What?

After that, things get a little more complicated. But not much. Any competent web developer or IT professional can get you set up with GZIP compression, for example, or troubleshoot slow database load times.

Bonus: check out Portent’s Development Architect Andy Schaff’s two-tiered ranking system of page speed optimizations to help you prioritize changes to make to your site.

Easy Wins, Big Advantage

If you’re ready to tackle site speed, we’ve got you covered. Learn the ins and outs of a faster site in our Ultimate Guide to Site Speed.

Other web speed tools:

PageSpeed Insights
Chrome User Experience Report

Compared to other digital marketing challenges, page speed is easy to address. And it has measurable results. But very few companies do the simple things that make a site fast. The good news is that you can gain a big competitive advantage if you just do the basics.

The post Site Speed is (Still) Impacting Your Conversion Rate appeared first on Portent.

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