Overtime is time worked beyond an employee's contracted hours. Here's what UK employers and workers need to know about pay rates, legal obligations, and how overtime affects holiday pay.
What is overtime pay?
Overtime pay is the rate an employee receives for hours worked beyond their normal contracted hours. In the UK, there is no statutory minimum overtime rate; employers are free to set their own rates, provided the overall pay for all hours worked does not fall below the National Minimum Wage.
Most employers pay a premium for overtime: commonly 1.25x or 1.5x the normal hourly rate ("time and a half") but this is a matter of contract, not law.
Is overtime pay a legal requirement in the UK?
UK law sets limits on overtime but does not require employers to pay a premium rate. The key rules are:
| Rule | What it means |
|---|---|
| No mandatory overtime rate | Employers can set any rate, including the same as normal pay, as long as total pay for all hours worked meets the National Minimum Wage. |
| No obligation to offer overtime | Employers are not required to make overtime available. |
| Voluntary by default | Unless the employment contract says otherwise, employees cannot be required to work extra hours. |
| Compulsory overtime must be contractual | If the contract includes a compulsory overtime clause, the employer can require extra hours — but must still meet National Minimum Wage across all hours worked. |
| 48-hour weekly limit | Under the Working Time Regulations 1998, employees cannot be required to work more than 48 hours per week on average (calculated over a 17-week reference period). Employees can opt out in writing. |
What are the different types of overtime?
- Voluntary overtime The employee chooses to work extra hours, and the employer chooses to offer them. Neither side is obligated. Refusing voluntary overtime cannot be used as grounds for disciplinary action or discrimination, and poor controls can even open the door to employee time theft in the workplace.
- Compulsory overtime The employment contract requires the employee to work additional hours when asked, which should be carefully coordinated with online shift planning for staff schedules. The employer must still pay at least the National Minimum Wage across all hours, and any premium rate should be specified in the contract.
- Non-guaranteed overtime The employer does not guarantee overtime will be available, but the employee is required to work it when offered. Common in hospitality and retail during busy periods; for example, Christmas trading or a seasonal spike, where reliable time clock software for tracking extra hours becomes essential. Courts have confirmed that non-guaranteed overtime must be factored into holiday pay calculations where it is worked regularly.
- Genuinely occasional overtime One-off or irregular extra hours that are not part of any regular pattern. This type of overtime is treated differently for holiday pay purposes.
How does overtime affect holiday pay?
This is the area where many UK employers get it wrong.
The legal position: Holiday pay should reflect a worker's normal remuneration, not just their basic contracted pay. If an employee regularly works overtime, that overtime must be included when calculating holiday pay for the first 4 weeks of statutory annual leave (the European-derived entitlement under the Working Time Directive).
The reference period: From April 2020, the reference period for calculating holiday pay for workers with variable or irregular pay is 52 weeks (using only weeks in which pay was actually received, up to a maximum of 104 weeks to find 52 paid weeks). This replaced the previous 12-week reference period.
What counts: Regular voluntary overtime, non-guaranteed overtime, and commission payments must be included in holiday pay calculations. Genuinely occasional overtime (worked so infrequently there is no established pattern) does not need to be included.
What employers often miss: If a member of staff consistently works Saturday shifts on top of their contracted hours, those hours form part of their normal remuneration. Paying holiday pay based on basic contracted hours alone creates a liability.
The 2014 Employment Appeal Tribunal (EAT) ruling in Bear Scotland v Fulton established that non-guaranteed overtime must be reflected in holiday pay. Subsequent case law has reinforced this for regular voluntary overtime.
Practical rule for employers: Calculate holiday pay using the 52-week average of actual earnings, including overtime, in the weeks worked, and consider following a structured approach similar to guides on calculating vacation pay for hourly employees. Exclude weeks where no pay was received.
How is overtime calculated?
There is no fixed formula required by UK law, but the most common approaches are:
- Time and a half (1.5x): The employee's normal hourly rate multiplied by 1.5. The most widely used overtime rate in the UK.
- Double time (2x): Normal hourly rate multiplied by 2. Often applied on bank holidays or Sundays in sectors like hospitality and retail, and related to how time and a half overtime rates are calculated.
- Enhanced flat rate: A fixed higher hourly rate for overtime, agreed in the employment contract.
- Same rate: Some employers simply pay the same hourly rate for overtime. Permitted under UK law, provided National Minimum Wage is met.
Important for National Minimum Wage compliance: If overtime hours push total hours worked above contracted hours without a matching increase in pay, the effective hourly rate across all hours worked can fall below the National Minimum Wage. Employers must check this, particularly for salaried staff asked to work significant additional hours.
What is Time Off in Lieu (TOIL)?
Time Off in Lieu (TOIL) is an alternative to paying overtime in cash. Instead of receiving a higher rate of pay, the employee banks the extra hours and takes them as paid leave at a later date.
TOIL arrangements must be agreed in the employment contract or a written agreement. Key points:
- The equivalent time off should reflect the overtime worked: some employers agree TOIL at a rate of 1.5 hours off per hour of overtime worked.
- TOIL leave must be taken within a reasonable period; employers should set a clear expiry timeframe.
- TOIL is not the same as unpaid overtime. If an employee works extra hours without either a TOIL agreement or overtime pay, this may fall foul of National Minimum Wage requirements.
Does overtime affect part-time workers differently?
For part-time employees, overtime typically begins once they exceed the hours specified in their own contract, not when they exceed full-time hours. For example, if a part-time employee is contracted for 20 hours per week, any hours beyond 20 are overtime, even if a full-time employee's standard week is 37.5 hours, and these extra hours also influence holiday accrual and statutory entitlement.
Employers should also be alert to the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000, which require part-time workers to be treated no less favourably than comparable full-time workers. This extends to overtime arrangements and links closely with monitoring absence rates and patterns among part-time staff.
What should an employment contract say about overtime?
A well-drafted employment contract should make clear:
- Whether overtime is voluntary or compulsory
- The rate of pay for overtime (or that it is paid at the basic rate)
- Any TOIL arrangement in place, supported where appropriate by robust employee timekeeping practices
- Whether there is an opt-out from the 48-hour weekly limit under the Working Time Regulations
Ambiguous contracts are the most common source of overtime disputes. If a contract says overtime "may be required," tribunals have found this can create a compulsory overtime obligation depending on context and custom.
Managing overtime hours
Employers are legally required to keep records sufficient to show compliance with the 48-hour weekly limit under the Working Time Regulations. Beyond the legal minimum, tracking employee hours accurately matters for three practical reasons:
- Payroll accuracy: overtime hours need to flow into the payroll calculation correctly, including for holiday pay reference periods, where practices like time clock rounding in payroll can affect total paid hours.
- Cost control: untracked overtime is one of the most common sources of unexpected labour cost overruns in shift-based businesses, so strategies for reducing employee overtime without harming productivity are essential.
- Dispute prevention: when an employee challenges their payslip or a holiday pay calculation, accurate records from time and attendance software are the employer's protection.
For shift-based businesses, the most reliable way to track overtime is to capture hours at source (when employees clock in and out at work) rather than reconstructing them at the end of a pay period. Implementing effective overtime tracking solutions ensures that records are complete and compliant. Shiftbase's time tracking records worked hours automatically against the schedule, flags deviations in real time, and exports payroll-ready data without manual re-entry. For businesses that also need to manage leave and absence alongside overtime, absence management keeps both in the same system.
- Easily clock in and out
- Automatic calculation of surcharges
- Link with payroll administration
