By law (The Working Time Regulations 1998), employees and workers must not work more than 48 hours a week on average. This is usually averaged over 17 weeks.
Limiting the hours people work is important for everyone's health, safety and wellbeing.
The 48-hour weekly limit applies unless the person:
- has 'opted out' of the maximum limit – this means they agree to work more hours
- does a job with exceptions under the law
There are different rules on working hours for young workers.
How to calculate average weekly working hours
- Add the total hours the employee worked in a 17-week period.
- Divide this total by 17.
If someone has worked for fewer than 17 weeks, use the number of weeks worked.
When the calculation period can be longer than 17 weeks
There are some exceptions to using 17 weeks to calculate average weekly working hours.
When there's a collective agreement
The 17-week period can be extended to a maximum of 52 weeks by a collective agreement. In this case, you need to divide the total by the relevant number of weeks in the agreement.
Junior doctors
The average weekly working hours for junior doctors are calculated over 26 weeks rather than 17.
Off-shore workers
The average weekly working hours for off-shore workers are calculated over 52 weeks rather than 17.
Opting out of the 48-hour weekly limit
An employee can choose to work more than an average of 48 hours a week. They do this by signing an 'opt-out agreement'.
This is a written agreement and should be separate from the employment contract.
Use our 48-hour opt-out agreement template
The employee does not have to agree to opting out of the 48-hour weekly limit. The employer must not cause the employee detriment because they do not opt out.
Detriment means someone experiences one or both of the following:
- being treated worse than before
- having their situation made worse
For example:
- their employer reduces their hours without good reason and without consulting with the employee
- they experience bullying
- they experience harassment
- their employer turns down their training requests without good reason
- they are overlooked for promotions or development opportunities
If an employee changes their mind about opting out
An employee can cancel an opt-out agreement at any time. They must give their employer notice if they want to do this.
This notice period depends on what's written in the opt-out agreement but can never be more than 3 months. If the agreement says nothing about it, then by law the notice period is 7 days.
Pay for going over the weekly limit
By law, employers do not have to offer a higher amount of pay than normal when someone works more hours because they've opted out.
Employers can choose to offer overtime pay. If so, it must be written in an agreement or the employment contract.
The employer must make sure the person is still getting at least national minimum wage for the average number of hours they work.
If someone has not opted out and works extra hours
If an employee has not opted out, they can work more than 48 hours in a week. If they do, they must work fewer hours across the calculation reference period to even out their average weekly hours.
Example of evening out average working hours
Sam usually works 48 hours a week. They have not opted out of the weekly limit.
This week, Sam's manager asks them to work 55 hours (7 hours more than usual). The request is because the business is short staffed. Sam agrees to work the extra hours.
To keep to the law, the manager must make sure Sam's weekly average is reduced back down to 48 hours. So they agree Sam will work 41 hours (7 hours less than usual) the following week.
Agreeing extra working hours
If an employer will require an employee to work extra hours, it should be written in the employment contract.
If it's not in the contract or there's not an agreement about working extra hours already in place, the employer should get agreement with the employee. They could do this by:
- explaining why the extra hours are necessary
- giving as much notice as possible
- explaining how their time can be adjusted to make sure their average hours do not exceed the 48-hour weekly limit
- setting out how the employer will protect their wellbeing and give them enough rest
If an employee has more than one job
If an employee is going to be working more than 48 hours on average across all their jobs, each employer should discuss the option of opting out with the employee.
The employee does not have to opt out of the 48-hour weekly limit and the employers must not cause them detriment because they do not opt out.
If the employee does not want to opt out, the employers should talk with them about their reasons. The employers should also do a health and safety risk assessment to check the effects of the employee working more than 48 hours a week.
The employers should talk through the results of the risk assessment with the employee and they could agree on:
- a reduction in hours
- how any risks can be solved or prevented
Example of agreeing working hours across 2 jobs
Tracey works an average of 30 hours a week in a factory. Tracey tells the factory manager that they have started an extra job working 20 hours a week in a cafe.
The factory manager works out that Tracey risks working more than 48 hours each week. They talk about all options and any health and safety risks, such as using machinery in the factory and being tired. They discuss the options for Tracey to opt out or reduce their overall working hours.
Tracey is enjoying both jobs and the extra money they bring in, so chooses to opt out of the 48-hour weekly limit.
Tracey agrees with both employers to regular check-ins to make sure that Tracey is not tired and at risk of using the machines in the factory.
If an employee thinks they're working too many hours
If someone thinks they're working more than 48 hours on average and they have not opted out of the weekly limit, they should first raise it with their employer.
If you have any questions about working time, you can contact the Acas helpline.