Holiday for irregular-hours and part-year workers: the 12.07% rule

This is general information about UK rules, checked on the date above. It is not legal advice, and rules change. For a decision that matters, check the sources below or ask a qualified adviser.

If you employ casual staff, zero-hours workers or seasonal workers, the usual way of counting holiday does not apply to them. For leave years starting from 1 April 2024, irregular-hours and part-year workers build up holiday through a specific calculation. Getting it wrong is easy, because the first question is one many employers skip: who actually counts as irregular-hours?

The short version

• Irregular-hours and part-year workers build up holiday based on the hours they have worked.¹
• Their entitlement is 12.07% of the hours worked in a pay period.²
• Employers may choose to pay holiday as “rolled-up” pay on top of normal pay, but only for these workers.³
• A rotating shift pattern with fixed hours does not make someone an irregular-hours worker.⁴

Who counts as an irregular-hours worker

According to Acas, someone is an irregular-hours worker if, under their contract, their hours in each pay period are variable. This usually includes people on zero-hours, casual or bank contracts.⁴

The test is about what the contract says, and not simply whether hours look uneven. Acas gives two helpful examples:⁴

• Sam is paid weekly, works a different number of hours each week, and has a contract saying hours will vary. Sam is likely to be an irregular-hours worker.
• Alex works a rotating two-week pattern of 15 hours and then 20 hours. The hours differ, but they are fixed, so Alex is not an irregular-hours worker.

Who counts as a part-year worker

Someone is a part-year worker if their contract requires them to work only part of the year, says there are periods of at least a week when they are not required to work and are not paid, and stays in place all year round.⁴ Acas’s example is a seasonal farm worker who only works and gets paid in spring and summer. Someone can still be a part-year worker with fixed hours.⁴

How the calculation works

GOV.UK sets out the method. The worker’s entitlement is 12.07% of the hours they worked in a pay period. It must be rounded up to the nearest hour if the entitlement is 0.5 of an hour or more.²

GOV.UK’s example is someone paid weekly who works 30 hours: 30 × 12.07 ÷ 100 = 3.621, so they earn 4 hours of leave, which they can take from their next pay period.²

Use GOV.UK’s holiday entitlement calculator to check your own figures. People on this system are still entitled to up to 5.6 weeks of statutory leave.¹

Paying for the holiday

There are two lawful approaches for these workers.

Paying when the holiday is taken

The worker is paid when they take leave. For irregular-hours and part-year work, a week’s pay is based on the worker’s average pay from the previous 52 weeks, counting only weeks in which they were paid. If no pay was paid in a week, you count back another week, up to a maximum of 104 weeks. If someone has fewer than 52 weeks of pay, you use the full weeks they have worked.⁵

Rolled-up holiday pay

Rolled-up holiday pay means spreading holiday pay across the year by adding an amount on top of normal pay, instead of paying when the holiday is taken. Employers can choose this for irregular-hours and part-year workers only.³

If you use it, you must calculate it at a rate of at least 12.07% of the worker’s total pay in the pay period, and show it as a separate payment on the payslip.³ Acas’s example is Jian, who earns £1,000 in June and should receive £120.70 of rolled-up holiday pay on top, shown separately.³

Rolled-up pay does not remove the need for people to actually take time off. Whichever method you use, you also need to keep records. Since April 2026, employers must keep records of holiday pay, including what it includes, for six years. See our article on the holiday records duty.

Where employers trip up

These are the mistakes we would look for first. They are our practical suggestions rather than a legal checklist.

1. Using the old method by habit. Leave years beginning on or before 31 March 2024 could use other methods.⁶ If your paperwork dates from then, check it has been updated.
2. Treating rotating shifts as irregular. Fixed patterns stay on the normal rules, as Alex’s example shows.⁴
3. Rolling up holiday pay for the wrong people. It only applies to irregular-hours and part-year workers.³
4. Forgetting to show it on the payslip. It has to be a separate payment.³
5. Working it out by hand each pay run. This is where rounding errors creep in. The sum is simple, but repeating it for every person, every pay period, is not.

What is changing next

Further changes are coming for people on zero-hours and low-hours contracts. Under the Employment Rights Act 2025, they will get the right to guaranteed hours if they want them, compensation if a shift is cancelled, shortened or moved, and reasonable notice of shifts. Acas says the government has not yet announced when these changes will happen.⁷ Keep an eye on this if you rely on flexible staff, because the way you build rotas may need to change as well. Our guide to rotas and working time covers today’s rules.

Systems like our HR and rota software can apply this calculation automatically, but only after someone correctly decides who it applies to. That decision is yours, and it depends on your contracts.