Holiday pay when software sets your hours: UK rules

When a scheduling system decides how many hours someone works each week, holiday entitlement and holiday pay get harder to track. Since April 2024, the Working Time Regulations 1998 have a separate scheme for irregular hours and part-year workers, which is exactly the group whose hours are often set by software. This page explains both schemes, how holiday pay is worked out, and what employers using scheduling tools should build in. It covers England, Wales and Scotland.

The short answer: most workers are entitled to 5.6 weeks' paid leave a year, capped at 28 days. A worker whose paid hours are wholly or mostly variable, or who works only part of the year, instead accrues leave at 12.07% of the hours worked each pay period, for leave years starting on or after 1 April 2024. Such workers can be paid holiday pay as a 12.07% uplift on each payslip, shown separately. Holiday pay is otherwise based on a week's pay, averaged over 52 weeks where pay varies.

The standard entitlement

A worker is entitled to four weeks' annual leave in each leave year (WTR 1998, reg 13) plus 1.6 weeks' additional leave, with the total capped at 28 days (reg 13A). These rules apply to workers who are not covered by the irregular hours scheme, and to all workers for leave years that began before 1 April 2024.

Irregular hours and part-year workers

Under regulation 15F, a worker is an irregular hours worker in a leave year if the number of paid hours they will work in each pay period is, under their contract, wholly or mostly variable. A part-year worker is required to work only part of the year, with periods of at least a week in which they are not required to work and are not paid (reg 15F). Zero hours contracts where a system offers shifts week by week are likely to fall within the first definition.

For leave years beginning on or after 1 April 2024, these workers accrue leave on the last day of each pay period at 12.07% of the hours worked in that period, up to 28 days a year (reg 15B). During sick leave or statutory leave, they accrue leave based on their average weekly hours over the previous 52 weeks (reg 15C).

Rolled-up holiday pay

For irregular hours and part-year workers only, the employer may pay holiday pay as a 12.07% uplift on pay for work done, paid at the same time as that pay (reg 16A). Any itemised pay statement must show the amount of holiday pay paid for the period (reg 16A(7)). Paying this way discharges the employer's liability to pay for that leave when it is taken (reg 16A(8)). The worker is still entitled to take the leave; the pay has simply been made in advance.

How holiday pay is calculated otherwise

A worker is paid a week's pay for each week of leave, calculated under sections 221 to 224 of the Employment Rights Act 1996 with changes. Where pay varies, the reference period is 52 complete weeks, or the number of complete weeks worked if less (reg 16). For irregular hours workers, the hourly rate of holiday pay is that week's pay divided by the average weekly hours used to calculate it (reg 16(1A)).

Where scheduling software fits

• Classification: whether someone is an irregular hours worker depends on their contract, not on the software. If the system offers shifts with no fixed hours, check whether the contract makes paid hours wholly or mostly variable.
• Accrual tracking: the 12.07% accrual is based on hours worked each pay period, so the hours recorded by the system must be complete and accurate, including training and time the worker is required to be at work.
• Payslips: if holiday pay is rolled up, payroll must show it as a separate amount on each statement.
• Booking leave: a worker still needs to be able to take leave. A rota tool that keeps offering shifts during booked leave, or makes leave hard to book, undermines the right.

If holiday pay is wrong

A worker can complain to an employment tribunal (reg 30). From 1 October 2026 the time limit is six months from the date the payment should have been made, or the date leave should have been allowed, where that date is on or after 1 October 2026; earlier cases keep three months (reg 30, SI 2026/954). Early conciliation through Acas normally comes first.

See also AI scheduling and shifts in the UK, per-task pay and the UK minimum wage and AI, platforms and UK worker status, and for sickness absence statutory sick pay when software tracks absence, and for magistrates, councillors and school governors time off for public duties. Northern Ireland has separate legislation. This page is general information, not legal advice.