I recently read an article titled “‘Beyond the call of duty’:lecturers top unpaid overtime figures” published by the Times Higher Education (THE) on the 24th Feb 2012, that on average academics work an extra 9.6 hours per week above and beyond the the call of duty. How on earth this figure was calculated I have no idea as 10 hours a day five days a week is quite a conservative amount. One of course also has the weekends to catch up on all the stuff you just didn’t get around to doing, and also gives you a chance to make a start on the stuff for the following week.
Even with a very conservative estimate of 60 hours a week, I am quite sure it is save to say that most academics don’t come anywhere close to getting all the work done that they would have liked to / ideally should have completed, even given a 60/70 hour week. This article on academic hours and glass ceilings from universitydiary.wordpress.com indicates that many work 70+ hours a week, some reaching perhaps as high as 90. This is certainly a far more accurate estimate especially when one considers the balancing act of Teaching, Administration, Email, Meetings, Organising Events / Activities, Research, Commercialisation & general interaction with colleagues that most academics must contend with.
One may also find this article quite interesting again from THE. Given the mapping of a 35 hour standard work contact to 168 hours a week, I would estimate an ideal (although still perhaps conservative) week for an academic should come in as at least a 284 hour week (thus allowing for a 70 hour average + an additional two days to catch up with all the stuff one should have ideally got around to).