It’s a surprisingly common mistake, and most businesses don’t realise they’re making it.
“We treat everyone the same.” It’s what every good employer aims for. But when it comes to part-time staff and bank holidays, a well-intentioned calculation can end up producing very unequal entitlement.
If you pro-rate holiday entitlement for part-time staff, which is exactly the right thing to do, there’s one easy step to miss.
And if you miss it, some employees end up with noticeably more paid time off than colleagues working the same hours.
Here’s what that looks like, and how to make sure your calculations are getting it right.
A quick example
Say you have two part-time employees, both working four days a week. You’ve pro-rated their entitlement correctly: 16 days each. Looks fair. But watch what happens.
Why does this happen?
Most UK bank holidays fall on a Monday. Mary works Mondays, so she benefits from them automatically. Tony doesn’t work Mondays, so he misses most of them entirely.
You’ve given both the same entitlement, but ended up with a gap of 4 days. Not because of any deliberate decision, but because bank holidays weren’t included in the pro-rata calculation.
How to fix it, and how The Holiday Tracker does it automatically
The fix is straightforward: include bank holidays inside the pro-rata calculation, rather than treating them separately.
Combine holiday and bank holidays
Before any calculation, add them together into a single total. A full-time employee with 20 days holiday and 8 bank holidays has a total entitlement of:
20 + 8 = 28 daysPro-rate the full total
Apply the part-time fraction to the combined figure, not just the annual leave portion. For someone working four days a week:
28 × 4/5 = 22.4 → rounded to 22.5 daysDeduct the bank holidays they actually receive
Some of that 22.5 days will land on bank holidays, days the employee is already getting off. Those are deducted, leaving a clear bookable balance.
22.5 − bank holidays on working days = bookable entitlementThe result: equal entitlement, fairly calculated
Both Mary and Tony now have the same overall entitlement of 22.5 days. The difference is simply in how those days fall.
Mary has more of her entitlement on fixed dates. Tony has more flexibility to book when he chooses. But both receive exactly the same total time off, which is what fair entitlement looks like.
The three-step summary
- 1 Combine holiday entitlement and bank holidays into a single total
- 2 Pro-rate that total based on the employee’s working pattern
- 3 Deduct the bank holidays that actually fall on their working days
This approach ensures that all part-time employees receive their fair share of entitlement, regardless of which days they work. It’s the difference between entitlement that looks equal and entitlement that actually is equal.
The Holiday Tracker applies this calculation automatically for every employee, so you don’t need to work through it manually. It keeps everything consistent from the start.
It also gives you a clear way to manage everything around it. Holiday requests, sickness, and other types of absence all sit in one place.
So you’re not just getting entitlement, you’re keeping holidays and absences organised in one place.
Want The Holiday Tracker to handle this for you?
If you’d rather not have to think about holiday entitlement, who’s off, and managing annual leave, you can try it here.
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