Work out statutory holiday entitlement
Full year, new joiners, leavers and bank holidays, for any working pattern.
The Working Time Regulations 1998 cap a worker's average working week at 48 hours, usually measured over a 17-week reference period, and guarantee 5.6 weeks of paid annual leave a year [1] [2]. The same Regulations set a 20-minute rest break for shifts over 6 hours, 11 hours of daily rest and a night work limit of 8 hours on average in every 24 [3] [4].
These rules sit at the junction of employment law and payroll. Hours recorded for the 48-hour average are the same hours that drive National Minimum Wage checks, holiday accrual for irregular-hours workers and the holiday pay reference period. When the hours data is wrong, every downstream figure is wrong with it.
This guide sets out each limit in the Regulations, who it applies to, how the averages are calculated with worked examples, which records an employer must keep, and how working time connects to the payroll run. It is written for employers, payroll administrators and the bureaux and software platforms that serve them.
Key takeaways
- The 48-hour weekly limit is an average, normally calculated over 17 weeks, and workers aged 18 or over can opt out in writing.
- Adult workers are entitled to a 20-minute break after 6 hours, 11 hours' daily rest and 24 hours' weekly rest (or 48 hours per fortnight).
- Night workers must not average more than 8 hours in 24, and unlike the weekly limit, nobody can opt out of the night limit.
- Statutory holiday is 5.6 weeks a year, capped at 28 days, with irregular-hours and part-year workers accruing at 12.07% of hours worked.
- From 6 April 2026, employers must keep adequate records of annual leave and holiday pay for six years.
- Under-18s have stricter, non-averaged limits of 8 hours a day and 40 hours a week.
What the Working Time Regulations cover
The Working Time Regulations 1998 (SI 1998/1833) implemented the European Working Time Directive into UK law and remain in force as retained, now assimilated, legislation [1]. They grant rights to "workers", a wider group than employees, which includes casual, agency and zero-hours staff [5]. Genuinely self-employed contractors fall outside the Regulations.
The Regulations combine two kinds of rule. Some are limits, which the employer must take all reasonable steps to keep within, and which are policed by regulators. Others are entitlements, such as rest breaks and holiday, which the worker enforces individually through an employment tribunal.
The table below summarises the core limits and entitlements for adult workers.
| Rule | Adult workers (18+) | Can the worker opt out? |
|---|---|---|
| Average weekly working time | 48 hours, normally over 17 weeks | Yes, in writing |
| In-work rest break | 20 minutes if working more than 6 hours | No |
| Daily rest | 11 consecutive hours between working days | No |
| Weekly rest | 24 hours per week or 48 hours per fortnight | No |
| Night work | Average of 8 hours in each 24 hours | No |
| Paid annual leave | 5.6 weeks, capped at 28 days | No |
Who enforces which rule
Enforcement is split. The Health and Safety Executive enforces the weekly working time limit, the night work limits and night work health assessments, while rest breaks and paid annual leave are enforced by the worker through the tribunal system [6]. HSE shares that role with sector regulators, including the Civil Aviation Authority, the Driver and Vehicle Standards Agency and the Office of Rail and Road [6].
Breaching a limit is a criminal offence under regulation 29, while a worker denied a break or leave can bring a complaint under regulation 30, normally within three months [1]. The Fair Work Agency, launched on 7 April 2026, is expected to take over statutory holiday pay enforcement once its powers are phased in [7].
Workers and jobs with different rules
Some roles are carved out of the weekly limit entirely. These include the armed forces, emergency services and police, security and surveillance roles, domestic servants in private households, seafarers, jobs requiring 24-hour staffing, and managing executives who control their own working time [2]. Mobile transport workers are usually covered by separate drivers' hours rules [8].
Where an exception removes a rest entitlement, the worker is generally owed compensatory rest instead, an equivalent period of rest taken later [8] [1].
The 48-hour average working week
The headline rule is that average weekly working time must not exceed 48 hours [2]. It is an average, not a weekly ceiling: a worker who has not opted out can work 55 hours one week and 41 the next without any breach, provided the average stays at or below 48 [5].
The reference period
The default reference period is 17 weeks. A collective or workforce agreement can extend it to as much as 52 weeks, junior doctors average over 26 weeks and offshore workers over 52 weeks [5] [2]. For a worker employed for less than 17 weeks, the average is taken over the weeks actually worked [5].
Days of annual leave, sick leave and family-related leave inside the reference period are "excluded days". Under regulation 4, the employer replaces them with the same number of working days from immediately after the period, so leave cannot be used to dilute the average [1].
Worked example: within the limit and in breach
The calculation is total hours worked across the reference period divided by the number of weeks [9]. The table compares two warehouse operatives over the same 17-week period, neither of whom has opted out.
| Worker A | Worker B | |
|---|---|---|
| Heavy weeks | 12 weeks at 52 hours = 624 | 10 weeks at 55 hours = 550 |
| Lighter weeks | 5 weeks at 38 hours = 190 | 7 weeks at 45 hours = 315 |
| Total hours | 814 | 865 |
| Average (÷ 17) | 47.9 hours | 50.9 hours |
| Outcome | Within the limit | Breach unless opted out |
Worker A's peak season is absorbed by the averaging. Worker B exceeds the limit, so the employer must either secure a voluntary written opt-out or reduce hours for the rest of the period.
What counts as working time
Working time includes job-related training, travel that is part of the job, working lunches, paid overtime, unpaid overtime the worker is asked to do, and on-call time at the workplace [9]. Travel between home and the first and last assignment counts where the worker has no fixed workplace [9].
It excludes unworked lunch breaks, on-call time away from the workplace where the worker is free, ordinary commuting to a fixed workplace, voluntary unpaid overtime and holiday [9].
On-call and sleep-in time is the area most often misjudged. Acas guidance states that the more control the employer has over the worker's activities, location and time, the more likely the time counts, and that a sleep-in at the workplace usually counts even while the worker is asleep [10]. A care worker required to stay on site and carry out three-hourly checks is likely to be working throughout [10].
Workers with more than one job
The 48-hour average applies to combined hours across all jobs [9]. Acas gives the example of a worker with 30 hours in a factory and 20 in a cafe, around 50 hours in total, where both employers should discuss the opt-out and carry out a risk assessment [5]. Employers should ask new starters about other employment as part of onboarding.
Opting out of the 48-hour week
Workers aged 18 or over can agree to work more than 48 hours on average by signing a written opt-out, for a fixed period or indefinitely [11]. Acas recommends keeping the agreement separate from the employment contract [5].
Voluntary, cancellable and protected
The opt-out must be voluntary. An employer can ask, but cannot dismiss or treat a worker unfairly for refusing, and Acas lists unexplained cuts to hours, refused training and being overlooked for promotion as examples of unlawful detriment [11] [5].
The worker can cancel at any time. The notice period is set by the agreement but cannot exceed 3 months, and where the agreement is silent the notice is 7 days [5] [11].
Who cannot opt out
Certain workers cannot sign an opt-out at all, as the table below shows.
| Group | Position |
|---|---|
| Airline staff | Cannot opt out |
| Workers on ships or boats | Cannot opt out |
| Road transport workers under EU-derived drivers' hours rules | Cannot opt out |
| Drivers of vehicles under 3.5 tonnes using GB domestic rules | Can opt out |
| Security guards on vehicles carrying high-value goods | Cannot opt out |
| Workers under 18 | Cannot opt out |
Source: [11].
An opt-out does not create a right to extra pay. Overtime premiums are a matter for the contract, although average pay must still meet the National Minimum Wage [5].
Rest breaks, daily rest and weekly rest
Rest entitlements cannot be opted out of, and they apply from the first day of work.
The three types of rest
Adult workers who work more than 6 hours in a day are entitled to one uninterrupted 20-minute break, 11 hours' rest between working days, and either 24 uninterrupted hours off each week or 48 hours each fortnight [3]. The break may be unpaid unless the contract says otherwise [3].
The break must be a single period during the working day, not at the start or end, and the worker must be allowed to leave the workstation [8]. A break interrupted by a recall to work does not count [8]. There is no statutory right to a second break on a 12-hour shift, although many contracts provide one.
Young workers
Workers above school-leaving age but under 18 have stricter rules, which cannot be averaged, as the comparison below shows.
| Entitlement | Adult workers | Young workers (under 18) |
|---|---|---|
| Maximum hours | 48 average per week | 8 per day and 40 per week, no averaging |
| In-work break | 20 minutes after 6 hours | 30 minutes after 4.5 hours |
| Daily rest | 11 hours | 12 hours |
| Weekly rest | 24 hours per week | 48 hours per week |
| Night work | 8-hour average limit | Generally barred 10pm to 6am |
A 16 or 17-year-old cannot work between midnight and 4am, and usually cannot work between 10pm and 6am, although exceptions exist in sectors such as hospitality, retail and agriculture [4].
Night work limits and health assessments
Night work carries its own regime because of the health risks of working against the body clock.
Who is a night worker
The default night period is 11pm to 6am. Employer and worker can agree a different 7-hour period in writing, provided it includes midnight to 5am [4]. A night worker is someone who regularly works at least 3 hours during the night period [4].
Night workers must not average more than 8 hours' work in any 24-hour period, normally over 17 weeks, and the limit cannot be opted out of [4]. Where the work involves special hazards or heavy physical or mental strain, 8 hours is an absolute cap in any 24 hours, with no averaging [4] [13].
Worked example: a four-on, three-off night rota
Regulation 6 divides total working time in the reference period by the number of days in the period, less one rest day for each 7 days [1]. A security officer working four 12-hour nights a week works 48 hours per 7 days. Dividing 48 by 6 qualifying days gives an average of 8 hours, which sits exactly at the limit.
Adding a fifth night in any regular pattern would push the average above 8 hours, so the employer would need to rebalance the rota. If the role were assessed as hazardous, each 12-hour shift would itself breach the absolute cap.
Health assessments and records
Employers must offer a free health assessment before a worker starts night work and at regular intervals afterwards, and the worker may decline [14]. If a health professional confirms night work is affecting the worker's health, the employer must offer suitable day work where possible [14].
Confidential records of assessments, and the dates on which declined assessments were offered, must be kept for 2 years [14].
Paid annual leave under the Regulations
Holiday is the part of the Regulations that touches payroll most directly, because every day of leave has to be valued.
Entitlement and accrual
Most workers are entitled to 5.6 weeks' paid leave a year, which is 28 days for a five-day week, and bank holidays can count towards it [15]. The statutory entitlement is capped at 28 days, so a six-day worker still receives 28 [15]. A worker on three days a week receives 16.8 days [15].
For leave years starting on or after 1 April 2024, irregular-hours and part-year workers accrue leave at 12.07% of hours worked in each pay period [16]. A worker who works 30 hours in a weekly pay period accrues around 4 hours of leave [15]. The table below compares the accrual methods.
| Worker pattern | Accrual method | Example |
|---|---|---|
| Full-time, 5 days | 5.6 weeks | 28 days |
| Regular part-time, 3 days | 5.6 x days per week | 16.8 days |
| Irregular hours or part-year | 12.07% of hours worked | 30 hours worked = about 4 hours' leave |
The same reform allowed rolled-up holiday pay for irregular-hours and part-year workers, paid as an uplift at the time of accrual instead of when leave is taken [17] [16]. The mechanics are covered in the Moonworkers guide to rolled-up holiday pay.
Holiday pay and the 52-week reference period
Workers receive a week's pay for each week of leave. For workers whose pay varies, it is based on average pay over the previous 52 weeks in which they were paid, looking back up to 104 weeks where needed [15]. Regular overtime and commission feed into that average for the first four weeks of leave, a point covered in detail in the article on overtime and holiday pay.
Carry-over and termination
A worker on 28 days can carry over up to 8 days if the contract allows, and leave lost through sickness can be carried over (up to 20 days for regular-hours workers) [15]. Full carry-over applies where the worker had no reasonable opportunity to take the leave or was not warned it would be lost [15].
On termination, untaken statutory leave must be paid out, even after gross misconduct, and over-taken leave can only be recovered from final pay if the worker agreed in writing beforehand [15]. The full statutory picture is set out in the Moonworkers guide to minimum holiday entitlement in the UK.
Record keeping and the payroll connection
The Regulations require "adequate" records rather than a prescribed format, but the definition of adequate has tightened.
What records the Regulations require
Regulation 9 requires records adequate to show that the weekly limit, night work limits and health assessment duties are being met, retained for 2 years [1]. The 2023 amending Regulations confirmed that employers need not record each worker's daily working hours, departing from the CJEU ruling in CCOO v Deutsche Bank [17]. Signed opt-out agreements should be held alongside these records [11].
From 6 April 2026, the Employment Rights Act 2025 added a duty to keep adequate records of annual leave and holiday pay for at least six years [18]. Those records must evidence entitlement, leave taken, carry-over, holiday pay and how it was calculated, and payments in lieu on termination [18].
| Record | Legal source | Minimum retention |
|---|---|---|
| Compliance with weekly and night limits | WTR regulation 9 | 2 years |
| Night worker health assessments | WTR regulation 9 | 2 years |
| 48-hour opt-out agreements | WTR regulations 4 and 5 | Kept as long as relied upon |
| Annual leave and holiday pay | Employment Rights Act 2025 | 6 years |
Working time and the National Minimum Wage
Long hours erode effective hourly pay. The National Living Wage for workers aged 21 and over is £12.71 an hour from 1 April 2026 [19]. A salaried worker on £27,000 a year averaging 45 hours a week across 52 weeks earns about £11.54 per hour worked, below the National Living Wage, even though the salary looks comfortably above a 37.5-hour equivalent.
Acas confirms that pay must average at least the minimum wage across the pay reference period for all working hours, including awake on-call and sleep-in time that counts as work [10]. Working time records and payroll records therefore have to reconcile.
Turning the rules into payroll data
The practical lesson is that hours captured for working time compliance are the same hours payroll needs for minimum wage checks, 12.07% accrual and the 52-week holiday average. Employers running UK payroll software for SMEs benefit when timesheet hours flow directly into the pay run rather than being re-keyed.
Bureaux that manage working time data across dozens of clients use a multi-client payroll platform to apply the same accrual and averaging logic consistently. Workforce and rota platforms can go further and embed the calculations through an HMRC-recognised payroll API, so that holiday accrual, minimum wage checks and Real Time Information submissions run from a single source of hours.
Check statutory holiday entitlement
Holiday entitlement is the Working Time Regulations right that employers calculate most often, particularly for part-time and part-year starters. The Moonworkers holiday entitlement calculator applies the 5.6-week rule and the 28-day cap to any working pattern.
Often 1 January or 6 April
Annual entitlement: 5.6 weeks · change
Statutory minimum is 5.6 weeks. Enter more if the contract gives extra leave.
Holiday entitlement
0 days
Fill in the working pattern, then press Calculate.
Need the holiday pay to go with it?
Moonworkers tracks entitlement, accrual and holiday pay automatically for every worker, with the 6-year record-keeping required since April 2026 built in.
Conclusion
The Working Time Regulations are often treated as an HR matter, but almost every rule in them produces a number that payroll consumes: hours for the 48-hour average, hours for the minimum wage check, hours for 12.07% accrual and weeks of pay for the holiday average. An employer whose time data and payroll data disagree cannot demonstrate compliance with any of them.
The direction of travel is towards more scrutiny of records. The six-year holiday record duty and the arrival of the Fair Work Agency shift the burden onto employers to evidence, not merely assert, that limits and entitlements were respected. Employers that treat working time data as payroll data will find that evidence already sits in the payroll history.
Frequently asked questions
Can an employer make the 48-hour opt-out a condition of the job?
No. The opt-out must be voluntary and in writing, and a worker cannot be dismissed or treated unfairly for refusing to sign it. The employer can ask, and can include an opt-out clause in documents offered to the worker, but the worker remains free to decline or to cancel later. Cancellation needs 7 days' notice unless the agreement specifies a longer period, which cannot exceed 3 months.
Does annual leave count towards the 48-hour weekly average?
No. Paid or unpaid holiday is not working time. Days of annual leave, sick leave and family-related leave in the reference period are excluded, and the employer adds the same number of working days from immediately after the reference period to keep the average accurate.
Are rest breaks under the Working Time Regulations paid?
Not automatically. The statutory 20-minute break for shifts over 6 hours can be unpaid, and whether breaks are paid depends on the employment contract. The break must be uninterrupted, taken during the shift rather than at the start or end, and away from the workstation.
How many hours can a night worker legally work?
A night worker must not average more than 8 hours in any 24-hour period, usually calculated over 17 weeks, and the limit cannot be opted out of. Where night work involves special hazards or heavy physical or mental strain, the 8-hour figure becomes an absolute cap in every 24 hours with no averaging. Employers must also offer free health assessments before night work starts and at regular intervals.
