Working time: introduction
## Relevant legislation
The legislation that applies to this page is as follows:
For pay reference periods commencing
* on or after 6 April 2015; National Minimum Wage Regulations 2015, regulations 7 & 17 to 50 * before 6 April 2015; National Minimum Wage Regulations 1999, regulations 14 & 20 to 29A
Employers are required to pay their workers at least the national minimum wage for the hours worked in each pay reference period.
The calculation for establishing a workers rate of pay for a pay reference period (NMWM09050) is;
P is the worker’s national minimum wage pay (NMWM09040), and
H is the hours worked.
The hours worked is based on the time worked (and treated as worked) as determined by the type of work (NMWM07010) being performed. It is therefore essential to establish the type of work being performed before the hours worked in a pay reference period can be established.
For national minimum wage purposes, there are different rules and calculations to consider for the hours worked for each type of work. These are: