The 30-second rule

In 1999 a Zona Research Inc. report popularized the "8-second rule," which held that if a company's Web page does not download within 8 seconds, users will go elsewhere. Since the report's publication, many Web sites appear to have lost track of the customer experience.

To understand the state of Internet performance, early last month Inc. surveyed 1,500 of the most popular Web sites, including AltaVista Co., America Online Inc., eBay Inc., MSN and Yahoo Inc. Unlike prior studies that used robot-based test traffic, we instead downloaded each home page, counting content components, measuring document sizes and computing best-case download times for a typical end-user connection via a 28.8K bit/sec modem. The results were curious and frightening. We found that the average home page uses 63K bytes of images, 28K bytes of HTML, 12K bytes of other file content and has a best-case first load time of 32 seconds. In other words, the average American users wait about 30 seconds the first time they look at a new home page. So much for the 8-second rule.

At first, one might imagine that second-tier sites are pulling down the 1,500-site average, but closer observation shows this to be false. The average load time for AltaVista, AOL, eBay, MSN and Yahoo home pages is about 25 seconds.

Sites such as AltaVista and AOL receive many repeat visits, with load time benefiting from document caching in the browser. To estimate cached download times, we assumed browsers retain all cacheable document components and respect relevant HTTP headers. Average best-case cached load time for the five first-tier sites is 4 seconds, quite a bit faster than the 1,500-site average of 7.8 seconds. These figures are good news for users and are more in line with popular notions about user patience, but they are best-case only. Actual performance also depends on factors such as network conditions and Web server load.

You're in good company if your home page is slow. Only about 100 sites had first-load times of less than 10 seconds. At the other end of the scale, more than 80 sites had first-load times above 60 seconds. In fairness, some sites that target a U.S. business audience are less concerned with dial-up performance.

Other interesting statistics: The average home page uses 23 distinct images with a total size of 63K bytes. JavaScript is taken for granted: 88 percent of the home pages used scripting, with an average of 10K bytes of script for sites that use it. Only 3 percent of pages used VBScript. About 36 percent of the pages load Cascading Style Sheet files, with an average size of 5.3K bytes. FRAMEs or IFRAMEs were found in 18 percent of the pages. Flash was found in 8 percent of pages, with an average size of 80K bytes.

Overall, these results cast a shadow over progress in user experience. One possible conclusion is that Internet users are more patient than previously thought. Another possible conclusion is that current Web site operators are inconsiderate of users. If you run a Web site, are your users giving you a break, or are you taking them for granted?

Chen is CTO for Appliant, a Seattle firm specializing in end-user experience management for Internet and intranet-based services. He can be reached at

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