The Working Time Regulations 1998 provide for a maximum working week of 48 hours. Unless they opt out, adult workers must not work more than an average of 48 hours per week over a specified reference period.
When calculating a worker's average weekly working time, the employer should ensure that it understands what counts as "working time" for the purposes of the Regulations. For example, it must be clear about how to deal with time spent travelling, overtime and time spent on call.
A specific formula applies to the calculation of working time if the worker has been absent for certain reasons during the reference period, for example on statutory annual leave.