The average UK worker is putting in over 13 extra working days a year, with one in four working for 34 days more than they're paid.
Data from the CV-Library job board makes it clear that the days of the traditional nine-to-five are long gone, with two thirds saying they work longer than they're supposed to and one in 10 working every day of the week.
See also: Is it time for a four-day week?
And despite 87% believing that every business should offer flexible working, nearly three quarters say they still don't have the option to work from home.
"It's become clear from the data that UK workers are putting in too much overtime. It's concerning to learn that up to one in 10 are even working seven days a week," says Lee Biggins, founder and managing director of CV-Library.
"Though technology may be great for enabling flexible working, it could also be disturbing the work-life balance of the nation's professionals as they continue to do work-related tasks outside of office hours."
Other countries have made moves to try and minimise the way work bleeds into family time. At the beginning of this year, for example, French workers won the right to ignore work emails out of hours.
Sweden, meanwhile, has been trialling six-hour days to see if this would increase staff productivity.
This is also something that the Green Party's keen on: in its May manifesto, it promised a four-day working week, with nobody having to work more than 35 hours overall.
The CV-Library survey found that three quarters of UK professionals would prefer a four-day working week, with over a third believing it would make staff more productive. Four in ten, though reckoned it might be stressful.
"It's clear that many believe that UK professionals would benefit from a four day week, despite there being mixed feelings around the subject," says Biggins.
"One thing is for sure, UK workers are at risk of becoming overworked if they continue to put in so much overtime and it's time they found themselves a healthier work-life balance."