The average American worker admits to frittering away more than two hours every day, with personal internet use by far the biggest distraction.
A survey by America Online and Salary.com suggests that while companies assume a certain amount of wasted time during the working day, employees are wasting about twice as much time as their employers expect.
They also calculated that employers spend $759 billion per year on salaries for which real work was expected, but not actually performed.
More than four out of 10 (45 per cent) of the 10,000 people polled cited "cyber-loafing" as their number one distraction at work.
Socializing with co-workers, conducting personal business, "spacing out," running errands, and making personal phone calls were the other popular time-wasting activities in the workplace.
Some employees adopted more creative ways of not working, however, such as running races up the staircase with co-workers. One respondent said: "the hurried walk around the office is not only a great way to look like you are busy, but also a good cardio exercise."
Men and women waste about the same amount of time per day, the survey found, although the older people are, the less time they waste at work.
But employees say they're not always to blame for this wasted time. A third of respondents cited lack of work as their biggest reason for wasting time, while almost a quarter said they wasted time at work because they feel as if they are underpaid.
Similar research in the UK has suggested that cyberloafing is symptomatic of employees feeling unmotivated and not being challenged in their jobs.
"To some bosses, that's a startling figure," says Salary.com's Bill Coleman. "Others, though, will view this extra wasted time as so-called 'creative waste' - wasted time that may well have a positive impact on the company's culture, work environment, and even business results."
And Coleman may well be right. Research carried out in Holland suggests that cyber-loafing workers are more productive than non-loafing colleagues because they prioritise and manage their workloads better and reduce stress by enjoying their day more.
Well, I'm reading this at work, so I guess it's all true!