Pro Rata Holiday Entitlement - How is it calculated (for late starters)?

[Armageus]

Random one, but having compared the governments online pro rata calculator vs the in-house developed system we use I've found a discrepancy.

The only problem is I can't work out how the government calculator gets to the answer.

Full time employee = 28 days holiday
Holiday year runs: 01/04/24 to 31/03/25
Employee start date: 23/09/24 (189 days left of the holiday year)

Based on my calculations they should get 14.5 Days holiday
28/365 * 189 = 14.49

However the government calculator is coming back with 16.5 Days?

Outcome - Calculate holiday entitlement - GOV.UK

www.gov.uk

 

[Armageus]

Because the Govt calculator starts from the 1st of the month they started, irrespective of the date they actually started. So 23rd Sept is taken as 1st Sept and their calculation is 28/12 * 7 = 16.33 = 16.5 rounded up.

Holiday entitlement calculator – calculations made easy | Moorepay

Calculating holiday entitlement can be complex. Use this formula to find out how to do complex calculations easily.

www.moorepay.co.uk

After 30 years of doing payroll, I didn't know the Govt calculator did that, I don't know why the Govt claculator does that and I'd use the 14.5 just as you did.

Edit : To test that, I've just changed your employee start date to 1st Sept and yep, the Govt calculator still says 16.5

That's absolutely bonkers (that it starts from the 1st of the month), but a relief that I'm not going mad

I don't know why the Govt calculator does that

I can only assume whoever coded it didn't know about Julian numbers for dates, as that makes it trivial to calculate days between two points