The Working Time Regulations (WTR) say that workers should not be required to work more than 48 hours on average in a week unless they have agreed in writing to do so. There are additional protections for night workers and young workers. However, workers who can decide the length of their working time themselves are not covered by these limits. This page looks at how the weekly working limits operate in practice. For help with working out what counts as working time and how to calculate average working time, see Calculating working time.