How to calculate holiday for zero-hours staff (the 12.07% rule)

Short answer: for irregular-hours and part-year workers, holiday accrues at 12.07% of the hours they actually work, for leave years starting on or after 1 April 2024. So for every 10 hours worked, a worker earns about 1 hour and 12 minutes of paid holiday. Below is why that figure exists and how to apply it without a spreadsheet.

Where 12.07% comes from

Almost all UK workers are entitled to 5.6 weeks of paid holiday a year. A standard working year is 52 weeks, minus the 5.6 weeks of holiday, which leaves 46.4 working weeks. Divide the holiday by the working weeks:

5.6 ÷ 46.4 = 0.1207, i.e. 12.07%

That’s the proportion of hours worked that should be “topped up” as paid holiday. It applies to people whose hours genuinely vary: zero-hours staff, casual workers, and part-year workers like seasonal housekeepers.

How to apply it

1. Total the hours worked in the pay period (or holiday year).
2. Multiply by 0.1207 to get the holiday hours accrued.
3. Pay holiday at the worker’s average rate when it’s taken (or, where permitted for irregular-hours and part-year workers in leave years from 1 April 2024, as rolled-up holiday pay shown separately on the payslip).

For example, a bar worker who does 90 hours in a month accrues 90 × 0.1207 ≈ 10.9 hours of paid holiday.

What changed in 2024

The Working Time Regulations were reformed for leave years beginning on or after 1 April 2024. The reform reinstated the 12.07% accrual method for irregular-hours and part-year workers and re-permitted rolled-up holiday pay for those groups. If your leave year started before that date, transitional rules may apply. Check current GOV.UK guidance.

Regular part-timers are different

If someone works the same days each week, you don’t use 12.07%; they simply get 5.6 weeks pro-rata. A person working three fixed days a week gets 3 × 5.6 = 16.8 days a year. The 12.07% method is specifically for hours that vary.

The easy way

Tracking this by hand, per person, every pay run, is exactly the kind of admin that eats an owner’s Sunday. WagePilot calculates accrual automatically as people work, including the 12.07% rule, and shows each person their live balance, so requests come into one approval inbox instead of a spreadsheet.

Want to sanity-check a figure yourself? Try the free holiday entitlement calculator.

This guide is general information, not legal advice. Check GOV.UK or a qualified adviser for your situation. WagePilot handles the tracking automatically, but you remain responsible for your own compliance.