What is holiday accrual?
Holiday accrual (or 'accrued holiday' or 'annual leave accrual') is when staff gradually earn holiday with each completed shift, which counts towards their holiday entitlement (also called 'leave allowance').
In the UK, part-time staff must be treated comparably to full-time workers in the same role. That means receiving the same pay rates, accessing the same training and getting paid annual leave at the same rate.
How does holiday accrual work?
If an employee works regular hours, it’s easy to calculate holiday entitlement based on hours worked. For example, if they work three days instead of the typical five, they’re entitled to 60% of the holiday allowance of their full-time colleagues, including bank holidays.
But if staff work variable hours each week, things get a little more complicated.
Staff ‘accrue’ holiday for the hours they’ve worked, and it’s added to their total holiday allowance, usually at the end of each pay period.
But how do you calculate holiday accrual? One way is to use our simple 12.07% holiday pay calculator...
Holiday accrual calculator:
How to calculate holiday accrual
Considering the variable hours your staff might accrue (and the complexity of working it out), we built this quick holiday accrual calculator to help you calculate holiday entitlement based on hours worked.
How to work out accrued holiday
First, to calculate holiday accrual, find the monthly figure by dividing the annual holiday allowance by 12. Then, multiply it by how many months have been worked.
For example:
28 (annual leave allowance) ÷ 12 (months in the year) x 4 (months worked) = 9.3 (accrued holiday)
(Alternatively, you can also use our holiday accrual calculator above or have a system that automates it instead!)
Why is 12.07% the default rate for holiday accrual?
Our 12.07% holiday pay calculator uses the default accrual rate as it reflects the statutory minimum annual leave allowance in the UK.
Here’s how that ‘12.07%’ rate is calculated:
5.6 weeks is the usual holiday allowance for full-time workers, out of 52 weeks. That means employees accrue their holiday in the remaining 46.4 weeks of the year (52 - 5.6 weeks). 5.6 divided by 46.4 is 0.1207, or 12.07%, so workers accrue holiday at a rate of just over 12%. For every 100 hours worked, 12.07 hours are accrued as annual leave entitlement.
Does the 12.07% rule always apply for holiday accrual?
No — there are two other things to think about.
First, you might offer additional leave on top of the statutory minimum. The calculator allows for this and adjusts the accrual rate accordingly.
Secondly, if staff can’t potentially work every week, for example, due to working term times only, the calculation is different again. For example, if they can only work 40 weeks a year, the holiday will accrue at a rate of 5.6/(40-5.6) = 16.2%.
It gets a bit more complicated than this, but we wanted to keep this calculator as straightforward as possible.
How does holiday accrual work with bank holidays?
Part-time staff should receive bank holidays as part of their entitlement on a proportional basis — it’s included within the accrual rate and shouldn't affect how to calculate accrued holidays.
How much holiday have I accrued?
This is information a manager or employer should have and keep visible to employees. But you can calculate holiday entitlement based on hours worked.
Staff get one-twelfth of their annual leave each month. So, if you've worked 3 months (and work 5 days a week and have 28 days holiday entitlement), you will have accrued a quarter of your holiday - 7 days.
How many days' holiday do you accrue per month?
Employees receive one-twelfth of their annual leave per month. Even with varying hours and contracts, both full-time and part-time staff should receive the same pay and holiday rates.
Next steps
You've worked out holiday accrual manually – but what about not having to calculate it at all? Here's how to stop doing this by hand (calculator or not).
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Editor's Note: This post was originally published in 2023 and updated for accuracy in January 2025, then in September 2026.
This article isn’t legal advice. It’s just for general information purposes. If you’re unsure about how holiday accrual rules apply to your specific case, contact a legal expert.