The study found that high stress levels, dull administrative tasks and the desire to be their own boss top the list of reasons for staff wanting to leave their jobs.
The findings, from a survey of more than 1,000 employees in a range of fields, show that staff are increasingly prepared to change careers to chase their dreams, City and Guilds said.
Wanting to be your own boss, high stress levels, and the desire to escape dull administrative work each trigger 20% of career switches, according to the survey.
It found that the longer people have been in their careers, the more likely they are to want to change direction. About 33% of IT professionals said they had considered changing careers after 10 years in the job.
Friends and colleagues also exert a strong influence over career decisions, the survey found, with 33% of IT professionals saying that chatting with friends led them to consider alternative career paths.
Chris Humphries, director general at City and Guilds, said many people saw turning freelance as a way to improve job satisfaction. "Self-employment is a popular choice as workers push job satisfaction up the agenda. Britain has always had a strong enterprise culture, but anyone considering the self-employment route needs a certain set of skills to succeed," he said.