How to Calculate Annual Leave Entitlement
Formulas and worked examples for calculating annual leave entitlement — full-time, part-time pro-rata, and mid-year starters — plus how public holidays factor in.
"How many holiday days do I actually get?" sounds like a one-line answer. Then someone joins in August, someone else works three days a week, and a third asks whether public holidays count on top — and suddenly you're doing fractions on the back of an envelope and hoping you got it right.
Getting entitlement wrong cuts both ways: under-credit someone and you've shortchanged them; over-credit and you'll be clawing days back at year-end. Here's how to calculate annual leave entitlement properly — with the formulas and worked examples for full-timers, part-timers, and mid-year starters.
Start with the full-time allowance
Everything flows from one number: the full-time annual allowance — the days a full-time employee gets in a complete leave year. You set this (within any legal minimum). Common figures sit somewhere in the 20–30 day range, and many countries set a statutory minimum below which you can't go.
A note on the law. Minimum paid leave varies by country — many set a floor, and some count public holidays as part of it while others don't. For example, the UK requires a minimum statutory entitlement that can include public holidays. This is general guidance, not legal advice — check the minimum where you operate before setting your number.
Once you've fixed the full-time figure, every other case is a fraction of it.
Full-time, full year
The easy case. A full-time employee who works the whole leave year simply gets the full allowance.
- Allowance: 25 days
- Worked: the full year
- Entitlement: 25 days
No maths required — this is your baseline for everything below.
Part-time (pro-rata)
A part-timer gets the same proportion of leave as a full-timer, based on the days they work. The cleanest formula is days-based:
Part-time entitlement = full-time allowance × (their days per week ÷ full-time days per week)
If a full week is 5 days and the full-time allowance is 25 days:
- 3 days a week: 25 × (3 ÷ 5) = 15 days
- 4 days a week: 25 × (4 ÷ 5) = 20 days
- 2.5 days a week: 25 × (2.5 ÷ 5) = 12.5 days
Expressing the result in days works neatly when someone has fixed working days. For irregular or shift patterns, many employers calculate leave in hours instead (full-time allowance in hours × their weekly hours ÷ full-time weekly hours), which avoids the awkwardness of part-days. There's a fuller walk-through in how to calculate pro-rata holiday entitlement, and the underlying idea — measuring everyone against a full-time benchmark — is explained in what is full-time equivalent (FTE)?.
Mid-year starters (and leavers)
Someone who joins partway through the leave year gets a slice of the allowance proportional to how much of the year is left:
Starter entitlement = full-time allowance × (months remaining ÷ 12)
(Use whole or part months — or, for more precision, days remaining ÷ days in the leave year.)
- Joins 1 April, leave year is Jan–Dec → 9 months remain: 25 × (9 ÷ 12) = 18.75 days
- Joins 1 October → 3 months remain: 25 × (3 ÷ 12) = 6.25 days
Leavers work the same way in reverse: entitlement is pro-rated to their last day, and accrued-but-untaken leave is usually paid out (while leave taken beyond what they'd accrued may be deducted).
All the cases in one table
Assuming a 25-day full-time allowance and a 5-day full-time week:
| Situation | Formula | Worked example | Entitlement |
|---|---|---|---|
| Full-time, full year | allowance | 25 | 25 days |
| 3-day week | 25 × (3÷5) | 25 × 0.6 | 15 days |
| 4-day week | 25 × (4÷5) | 25 × 0.8 | 20 days |
| Joins 1 April | 25 × (9÷12) | 25 × 0.75 | 18.75 days |
| Part-time + mid-year (3-day, joins 1 July) | 25 × (3÷5) × (6÷12) | 15 × 0.5 | 7.5 days |
Notice the last row: when someone is both part-time and a mid-year starter, you apply both fractions. Pro-rata the allowance for their hours, then pro-rata again for the part-year.
What about the fractions?
Pro-rata maths produces half- and quarter-days (18.75, 7.5, 12.5). You've three honest options: allow half-days (most flexible), round up to the nearest half or whole day (employee-friendly), or track everything in hours so the awkward fractions simply become a tidy number of hours. Pick one, write it into your leave policy, and apply it to everyone the same way. What you should not do is silently round down — that quietly shortchanges part-timers.
Do public holidays sit on top, or inside?
This is the question that causes the most confusion, and there's no universal answer — it's a choice you state explicitly:
- On top: the employee gets their annual leave allowance plus public holidays as additional paid days off. (Common where allowances are quoted as "25 days + bank holidays".)
- Inside: public holidays are counted within the total allowance. (Common where a single larger number, e.g. "33 days", already bundles them in.)
Whichever you choose, be consistent — and remember public holidays differ by location, so a multi-country team won't all have the same days. Absenca pulls in the correct public holidays per country automatically; you can browse, for instance, UK holidays for 2026 or US holidays for 2026.
A note on accrual vs. up-front
The figures above assume entitlement is granted for the period worked. Separately, you decide when it becomes available: all up front at the start of the leave year, or accrued gradually (e.g. 1/12 each month). Accrual changes how much someone can book early in the year, not their total for the period. The interaction with carry-over is covered in holiday carry-over and leave accrual explained.
How Absenca calculates it for you
Absenca does all of this maths automatically. Set the full-time allowance once, and it pro-rates correctly for part-timers and mid-year starters, handles monthly or annual accrual, and decides public-holiday treatment per office location — with the right holidays for each country built in. Balances update the moment a request is approved, so the number on screen is always the real one. No envelope, no fractions by hand.
It's free for up to 15 people (a real free tier, not a trial), then $0.75/user/month after that.
Frequently asked questions
What's the formula for pro-rata annual leave? For part-timers: full-time allowance × (their days per week ÷ full-time days per week). For mid-year starters: full-time allowance × (months remaining ÷ 12). If someone is both, apply both fractions. For more detail and edge cases, see how to calculate pro-rata holiday entitlement.
Do public holidays count as part of annual leave? It depends on how you've defined your allowance — they can sit on top or be included. There's no global rule, and statutory minimums treat them differently by country. Decide, state it clearly in your policy, and apply it consistently.
How do I handle the half-days that pro-rata produces? Allow half-days, round up to the nearest half or whole day, or track leave in hours so the fractions disappear. Whatever you pick, write it down and apply it to everyone equally — never silently round down.
What's the minimum holiday I have to give? That varies by country — many set a statutory minimum, sometimes inclusive of public holidays and sometimes not. This is general guidance, not legal advice; check the minimum in your jurisdiction before setting your full-time allowance.
Stop calculating entitlement by hand — Absenca pro-rates, accrues, and tracks every balance automatically, free for up to 15 people. Next: holiday carry-over and leave accrual explained.