Think viewing a few websites on a smartphone doesn't use much data? Think again.
The average size of a web page continues to grow unabated, a trend that mobile users in particular should take note of.
According to the website HTTP Archive, which regularly studies the top 10,000 most-visited sites online, the average web page now weighs in at about 1.3 megabytes, up about 35 per cent in the last year.
It's not a big data hit when accessing the web at home but it's a different story for users with limited data allowances for their mobile phones.
And don't be fooled by the look of streamlined mobile-friendly sites that are sometimes displayed on smartphones and tablets. While those sites strip away much of the visual excess that doesn't translate well to a small screen, they're not always a lean download.
HTTP Archive suggests the average web page when browsing on a mobile device – accounting for the fact that some websites have mobile-optimized pages and others don't – is about 720 kilobytes.
"That is quite large, that size has really grown a fair bit," says Guy Podjarny, an Ottawa-based web performance researcher who works for the company Akamai.
"Anything that is over the 700 kilobytes or 800 kilobytes range I would mark as too heavy for mobile."
Given that many mobile providers sell plans that start at 150 megabytes a month, basic web browsing – nevermind streaming of audio or video, which quickly gobbles through data – could quickly deplete that allotment. Accounting for HTTP Archive's average of 720 kilobytes per page, a user could visit about 210 websites, or about seven a day, before exceeding their limit.
Part of the growth in web page size can be attributed to the demand for more aesthetically pleasing designs with more multimedia, Podjarny says. Plus, users equipped with high-end smartphones and monitors are now viewing the web with super-sharp screens, a trend that's pushed web developers to use better – and larger to download – images.
"The (newer higher-resolution) images are four times the pixels of a regular image and three times the file size usually," Podjarny says.
Because it can be technically complex to serve up the high-resolution images only to the users with the extra-sharp screens, all users often get the larger images, even if they can't see the difference themselves, he adds.
And some websites that appear to be streamlined with minimal graphics and photos may be just as large to download, Podjarny says, because the extra content is often being downloaded anyway but is hidden for mobile users.
"There's something called responsive web design and while it helps address the user experience aspect – the usability of the page by making it look like a mobile website – it actually hardly ever reduces the byte count," he says.
"There are intelligent techniques to create responsive websites that don't load unnecessary content but the vast, vast majority of responsive websites out there don't use it.
"It all comes down to the fact that you're downloading a large amount of content and you're either hiding or shrinking it. It leads to mobile websites that look and interact like mobile websites but are over one megabyte or two megabytes in size."
The growing size of websites is user-unfriendly, says Lee Brooks, product marketing manager at Sandvine, a Waterloo, Ont.-based computer network company.
Many users are already overly cautious about their mobile usage, afraid of racking up expensive bills, and aren't freely enjoying their access to the web and multimedia content on the go.
"People enjoy using services more when they know in their mind how much it's going to cost," Brooks says.
"If I'm constantly nervous about going over a quota, am I really making full use of that service and do I have the best possible quality of experience?"
Podjarny says it doesn't help users that service providers often oversimplify how consumers should calculate their data usage on the mobile web.
According to Bell's mobile data calculator, the company estimates the average website eats through 170 kilobytes when browsed on a phone or tablet. Rogers estimates a basic text-filled web page comes in at about 100 kilobytes or a "content-rich" site averages about 333 kilobytes of data.
Podjarny says those numbers underestimate today's typical mobile web surfing experience "by a pretty large margin."
"These numbers are not entirely far-fetched for dedicated mobile websites but many of the websites you will browse are not."