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Holiday pay for irregular-hours and part-year workers: a guide for employers
These workers are not on 5.6 weeks at all. They accrue 12.07% of hours worked per pay period under reg 15B. And 104 weeks is a conditional bound, not the reference window everyone treats it as.
Irregular-hours and part-year workers are where UK holiday goes wrong most often, and the reason is structural rather than careless.
Since leave years beginning on or after 1 April 2024, these workers are not on the familiar entitlement at all. Instead they build up an accrued entitlement under reg 15B of the Working Time Regulations 1998 (WTR), paid under a reg 16 mechanism that imports the Employment Rights Act 1996 (ERA) with its own modifications.
There is no statutory holiday year, either. Each leave year is anchored to the date in the contract, or failing that to the anniversary of the start date (reg 13(3)). So you track the boundaries per person, rather than reading them off one calendar.
TL;DR
- Ordinary statutory leave is four weeks plus 1.6 weeks, with the aggregate capped at 28 days — two separate entitlements, not one 5.6-week figure that splits
- Irregular-hours and part-year workers accrue at 12.07% of hours worked in each pay period instead, for leave years starting on or after 1 April 2024
- That accrual replaces the ordinary entitlement for those workers; there is no 5.6 weeks left to pro-rate
- A week’s pay is averaged over the last 52 weeks in which pay was payable, looking back no further than 104 weeks
- Rolled-up holiday pay is lawful for reg 15B leave only, and it must be itemised on the payslip
Which workers does the 12.07% accrual apply to?
Only those meeting the definitions in reg 15B. That is narrower than “anyone whose hours move about”, and getting it wrong costs money in both directions.
For someone inside the definitions, the accrued entitlement replaces the ordinary one rather than sitting alongside it. Ordinary entitlement is restricted to workers the accrual rule does not reach (reg 13(1), via reg 13(A1)(b); reg 13A carries the same switch). So you have no 5.6 weeks to pro-rate. You have one accrued entitlement, built up pay period by pay period.
For someone outside them, 12.07% accrual has no statutory footing. A part-timer on a fixed two-day week keeps the ordinary entitlement (regs 13 and 13A). Applying an accrual percentage to them is a decision you would have to defend on its own terms, not a rule the WTR supplies.
One thing that is guidance rather than regulation: gov.uk states the ordinary entitlement as 5.6 weeks and describes bank holidays as capable of counting toward it. No WTR provision says that. Treat the contract as the governing document on bank holidays, and do not cite the Regulations for the point.
Next: classify each contract against reg 15B before doing any arithmetic. Job title and rota volatility are not the test.
Is “5.6 weeks” a figure you can rely on?
No — it appears nowhere in the Regulations, and that shapes how you should reason about the rest.
The ordinary entitlement is four weeks (reg 13(1)) plus 1.6 weeks (reg 13A(2)(e)), with the aggregate capped at 28 days (reg 13A(3)). The two limbs are separate entitlements that happen to add up, not one figure that splits.
How does the accrual actually work?
Leave accrues at 12.07% of the hours worked in each pay period, credited on the last day of that pay period (reg 15B(3)(b)). The balance at any moment is accrued leave, plus leave carried forward, less leave taken (reg 15B(2)).
| What it governs | The rule | Provision |
|---|---|---|
| Ordinary statutory leave | 4 weeks + 1.6 weeks, aggregate capped at 28 days | reg 13(1), reg 13A |
| Irregular-hours / part-year accrual | 12.07% of hours worked, last day of each pay period, capped at 28 days per leave year | reg 15B(3)(b), 15B(4) |
| Rounding | A fraction of an hour rounds up to a full hour at 0.5 hours or more | reg 15B(5) |
| Hourly rate for reg 15B leave | A ÷ B — a week’s pay over average weekly hours | reg 16(1A) |
| Reference period | 52 weeks in which pay was payable, or complete weeks employed if fewer | reg 16(3)(e) |
| Look-back | Up to 104 weeks, and only where a week had no remuneration payable at all | reg 16(3)(f)(i) |
| Accrual during sick or family leave | A three-step calculation, not 12.07% of hours worked | reg 15C |
| Rolled-up pay | 12.07% uplift on remuneration for work done — reg 15B leave only | reg 16A(1)–(2) |
One caveat needs deliberate handling: the cap is expressed in days while accrual is measured in hours, and the regulation supplies no conversion (reg 15B(4)). Converting needs a normal-day-length assumption the WTR does not give you.
Next: hold the accrual in hours in your own records and check the cap as an explicit step. A silent conversion is an assumption nobody wrote down.
What has to be included in a week’s pay?
More than basic pay. You owe a week’s pay for each week of leave taken (reg 16(1)). For leave under regs 13 and 15B, a week’s pay includes three things (reg 16(3ZA)):
- payments, including commission, intrinsically linked to the performance of tasks the employee is obliged to carry out under their contract;
- payments for professional or personal status relating to length of service, seniority or professional qualifications;
- other payments, such as regular overtime, paid in the 52 weeks preceding the calculation date.
Now the part that is routinely overstated: only regs 13 and 15B are named in that list. The 1.6 weeks under reg 13A is absent from it, which is not the same as a rule that reg 13A leave may be paid at basic pay.
Three things follow. Reg 13A leave is still a week’s pay (reg 16(1)). Because it is what remains once the reg 16(3ZA) components are set aside, it is derived rather than independently measured, so calling it “basic pay” overstates the difference. And no provision orders reg 13 leave against reg 13A leave when someone takes a mix of the two: taking reg 13 first is a convention, not a statutory rule.
For a reg 15B worker the split does not arise at all. One entitlement, one rate.
Next: check whether your payroll pays commission and regular overtime on the whole of the leave year or only on part of it.
How far back do you look to average a week’s pay?
Fifty-two weeks, and in most cases no further. The twelve-week references in ERA ss.221 to 224 are replaced with either the number of complete weeks employed, where that is under 52, or 52 in any other case (reg 16(3)(e)).
The 104-week bound comes into play only where a week is skipped because no remuneration at all was payable for it — the case under s.223(2) or s.224(3) of the Employment Rights Act 1996 (reg 16(3)(f)). Even then it only limits how far back you may reach while hunting for paid weeks.
So 104 weeks bounds the search. It is not the window you average over. If no zero-pay week exists, it never engages. And where fewer than 52 paid weeks turn up inside the bound, the divisor becomes the number of weeks actually found (reg 16(3)(f)(ii)).
A week paid statutory sick pay or holiday pay is a paid week, not a zero-pay week.
Next: two different tools answer two different questions. gov.uk’s holiday entitlement calculator returns a quantity and never a monetary figure. The holiday pay calculator returns money: what a period of leave is worth under reg 16.
When is rolled-up holiday pay lawful?
For reg 15B leave, and nothing else. The provision is drafted by reference to that leave only (reg 16A(1)), and allows a 12.07% uplift on remuneration for work done (reg 16A(2)).
For anyone else, it does not reach. Reg 13 and reg 13A leave for a regular-hours employee sits outside it, and a 12.07% uplift on their pay is not authorised.
Two obligations travel with the choice:
- Someone on rolled-up pay who goes on sick or statutory leave must instead be paid, for each pay period of that leave, the average holiday pay they received per pay period across a 52-week relevant period beforehand (regs 16A(4) to (6)).
- The itemised pay statement has to show the holiday pay paid in the period (reg 16A(7)). Easy to miss when the uplift is folded into a single gross figure.
Next: check a payslip. If the uplift is invisible on it, reg 16A(7) is not satisfied however correct the arithmetic is.
How does leave accrue while someone is off sick?
On a separate provision, not the ordinary 12.07%-of-hours-worked rule — there are no hours worked to apply it to (reg 15C).
The calculation runs in three steps (reg 15C(2)): average weekly hours over the relevant period before the leave started; 12.07% of that, giving hours accrued per week of leave; multiplied by the weeks in the pay period. The relevant period is the 52 weeks ending the day before the leave started, or shorter where employment is shorter (reg 15C(3)). Weeks with any sick or statutory leave are discounted, while zero-hour weeks still count (reg 15C(4)). Earlier weeks backfill to reach 52 (reg 15C(5)), bounded at 104 weeks (reg 15C(6)).
That 104-week bound belongs to reg 15C and to accrual. It is not the reg 16(3)(f) look-back, which belongs to pay and triggers on a week with no remuneration payable. Different provisions, different triggers, and one of the easiest pairs in the WTR to run together by accident.
Next: check which of the two 104-week rules your payroll is applying, and to which calculation.
What do employers most often get wrong?
| The mistake | What the rule actually says | Provision |
|---|---|---|
| Applying 5.6 weeks to a zero-hours worker | The ordinary entitlement is displaced entirely, for leave years from 1 April 2024 | reg 15B |
| Assuming 12.07% covers every variable-hours worker | It reaches reg 15B workers only; applying it wider understates what an ordinary part-timer is owed | reg 15B |
| Treating 104 weeks as the reference window | It is a conditional bound, engaged only where a week had no remuneration payable at all | reg 16(3)(f) |
| Excluding commission and regular overtime from a week’s pay | Both count for regs 13 and 15B leave | reg 16(3ZA) |
| Rolling up holiday pay for workers who are not reg 15B workers | They sit outside the rolled-up provision entirely | reg 16A |
| Confusing the accrual backfill with the pay look-back | The first governs accrual during sick leave, the second governs pay | reg 15C(6), reg 16(3)(f) |
| Forgetting the payslip line | The payslip must show the holiday pay paid in the period | reg 16A(7) |
Next: run this table against your last payroll export and check which row you are on.
gov.uk’s guidance is at Calculating holiday pay for workers without fixed hours or pay. The older /guidance/ path for the same title no longer resolves, so update any bookmark still pointing at it.
How does Taito.ai help with this?
Reg 15B accrual is a per-pay-period calculation against hours actually worked. Taito.ai is a people operations system that sets this accrual up per worker, against each contract’s own leave year, and keeps it maintained automatically as hours are recorded.
Sources
- Working Time Regulations 1998 — regs 13, 13A, 15B, 15C, 16 and 16A
- Employment Rights Act 1996 — ss.221 to 224
- GOV.UK — holiday entitlement
- GOV.UK — calculating holiday pay for workers without fixed hours or pay
Reg 15B applies to leave years beginning on or after 1 April 2024. Where the exact wording matters, follow the link and read the regulation.
Disclaimer
Taito.ai does not provide legal, tax or accounting advice. This article is general information about the law as it stood on the date above, not advice on your situation, and it is not a substitute for it. Rates and thresholds change. Check with a qualified adviser before acting on anything here.
