How to calculate pro rata holiday
To calculate pro rata holiday, multiply the number of days you work each week by 5.6. That gives the legal minimum for most workers on regular hours. If you work 3 days a week, you get at least 16.8 days a year (3 × 5.6). The total is capped at 28 days. If you start part-way through the leave year, multiply that figure by the share of the leave year that is left.
The calculator below does both sums for you. Enter your days and hours, then your start date.
No data is stored on our servers. Everything stays in your browser. Privacy policy
How to calculate pro rata holiday: the formulas
Pro rata means "in proportion". Your holiday is a full-time year's holiday, scaled to the part of the week you work and the part of the leave year you are employed. Pick the line that fits you.
| Your situation | Formula |
|---|---|
| You work fewer days a week, all year | Days you work each week × 5.6 |
| You work fewer hours, and holiday is counted in hours | Hours you work each week × 5.6 |
| Your employer gives full-timers more than the legal minimum | Full-time holiday × your weekly hours ÷ full-time weekly hours |
| You start part-way through the leave year | Your full-year figure × days left in the leave year ÷ days in the leave year |
| You are leaving part-way through | Use the termination calculator: leaving has its own formula |
The cap. Statutory holiday stops at 28 days, however many days a week you work. A part-timer is always under the cap: 4 days a week is 22.4 days, 2 days a week is 11.2 days.
Who this is for. These formulas are for people who work the same pattern all year. If your hours change from week to week, or you only work some weeks of the year, you build up holiday as you work instead (12.07% of the hours you work, for leave years from 1 April 2024, in England, Scotland and Wales; Northern Ireland has no 12.07% rule). Use the irregular hours calculator.
Bank holidays. The law does not give you bank holidays on top. Your employer can count them as part of your 5.6 weeks. If your contract adds them on top, see bank holidays for part-time workers.
Four worked examples
Part-time, 3 days a week — Aisha
Aisha works 3 days a week, on regular hours, all year. Her employer gives the legal minimum.
3 × 5.6 = 16.8 days a year.
That is the same as 5.6 weeks: one "week" for Aisha is 3 days.
Part-time, in hours — Aisha again
Aisha's 3 days are 7.5 hours each, so she works 22.5 hours a week. Her employer counts holiday in hours.
22.5 × 5.6 = 126 hours a year.
Check: 16.8 days × 7.5 hours = 126 hours. Both methods give the same answer when every working day is the same length.
Part-time with more than the legal minimum — Ben
Full-timers at Ben's work get 30 days a year, bank holidays included, for a 37.5-hour week. Ben works 22.5 hours a week.
30 × 22.5 ÷ 37.5 = 18 days a year.
That is more than the 16.8-day minimum for 3 days a week, as it must be: when full-timers get more than the minimum, part-timers get more too, in proportion to their hours.
Part-time and starting mid-year — Aisha starts on 1 July
Aisha's leave year runs from 1 January to 31 December 2027: 365 days. She starts on 1 July 2027. From 1 July to 31 December, counting both days, is 184 days.
16.8 × 184 ÷ 365 = 8.47 days → 8.5 days.
It rounds up to 8.5 because this is her first year in the job: employers cannot round part days down, and in the first year they must round up to the nearest half day.
Some employers work out the first year month by month instead, giving one-twelfth of the year's holiday at the start of each month. That changes how much you can take at a given point, so ask which method your employer uses.
You're joining partway through the leave year
This is the straightforward case. Your employer works out how much of the leave year is left to run from your start date, and gives you that proportion of a full year's entitlement.
The method: your entitlement is your full year's holiday multiplied by the proportion of the leave year left on the day you start (Working Time Regulations 1998, regulation 13(5) and regulation 13A(5)). To find that proportion, count the calendar days from your start date to the last day of the leave year (inclusive) and divide by the total number of days in the leave year. Your full year's holiday is 5.6 weeks a year under regulations 13 and 13A, which is 28 days for a 5-day week and fewer days for part-time work.
This is a calendar-day method, not a working-day method — weekends and bank holidays inside the remaining period are not stripped out before you divide, because the 28-day (or 5.6-week) entitlement already bakes in an average working pattern. One wrinkle worth knowing: because you're partway through your first year of employment, the half-day rounding rule below applies to you as a firm requirement, not just an employer's choice.
Joining — Priya starts a five-day-a-week role on 1 September
Priya's leave year runs 1 April 2026 to 31 March 2027 (365 days), and her full entitlement for a five-day week is 28 days. She starts on 1 September 2026, leaving 212 days remaining in the leave year (1 September to 31 March inclusive).
212 ÷ 365 × 28 = 16.26 days → rounded up to 16.5 days (mandatory, as this falls in her first year of employment).
You're leaving partway through the leave year
This calculator does not do the leaving sum. Use the termination holiday calculator, which asks how much leave you have already taken.
This is not the joining calculation run backwards. When you leave a job, your final holiday pay is governed by a specific statutory formula — Working Time Regulations 1998, regulation 14 — and almost no consumer-facing site sets it out in full.
If your contract does not set a different sum, regulation 14 gives you:
(A × B) − C
- A — your leave entitlement under regulations 13 and 13A (the full 5.6 weeks, pro-rated for part-time hours)
- B — the proportion of your current leave year that had expired on your last day
- C — the leave you've already taken in that leave year
In plain terms: work out what you'd have accrued by your leaving date if you'd stayed the whole year (A × B), then subtract what you've already used (C). What's left is what your employer owes you in your final pay. It matters that C is taken away after the proportion is calculated — not before — because that's what makes this genuinely different from the joining sum, where there's no "already taken" figure to subtract at all.
There's also a 2024 addition worth knowing about if you're carrying leave from an earlier year: regulation 14(6), in force since 1 January 2024 under SI 2023/1426, says that when your job ends you must also be paid for untaken leave carried forward from a previous leave year under regulation 13(14), (15) or (17) or regulation 13A(7) or (7A) — not just leave from the current year. It replaced regulation 14(5), which covered only leave carried forward under the coronavirus rule in regulation 13(10) and (11).
Leaving — Tom resigns after taking some leave already
Tom's leave year runs 1 January to 31 December 2026 (365 days). His full entitlement is 28 days (A). He resigns with his last working day on 15 June 2026 — 166 days into the leave year (B = 166 ÷ 365). He has already taken 10 days' leave (C) since 1 January.
A × B = 28 × (166 ÷ 365) = 12.73 days accrued by his leaving date.
(A × B) − C = 12.73 − 10 = 2.73 days owed in his final pay (an
employer applying the optional half-day round-up would pay 3.0 days).
You're changing your hours partway through
If your working pattern changes mid-year — say from full-time to part-time, or a change in your contracted days — a fair approach is to split the leave year into two (or more) periods at the point your hours changed, work out a separate pro-rata entitlement for each period at the pattern that applied during that period, and add the results together.
Neither the Working Time Regulations nor ACAS's holiday guidance sets a formula for a change of hours part-way through a leave year. Splitting the year is a fair way to do it, and it is how Sam's example below works. This calculator handles one work pattern at a time, so run it once for each period and add the results. Check the method with your employer.
Changing hours — Sam drops from five days to three days a week
Sam's leave year runs 1 January to 31 December 2026. He works a five-day week (28 days' full entitlement) from 1 January to 30 June — 181 days — then drops to a three-day week (16.8 days' full entitlement, being 5.6 weeks × 3) from 1 July to 31 December — 184 days.
Period 1: 181 ÷ 365 × 28 = 13.88 days.
Period 2: 184 ÷ 365 × 16.8 = 8.47 days.
Total: 13.88 + 8.47 = 22.35 days → rounded up to 22.5 days.
The rounding rule that works in your favour
Pro-rata sums rarely land on a whole number of days, so a rounding rule is needed — and the rule is asymmetric by design. Per ACAS guidance, employers can never round a part-day down. During your first year of employment, they must round any part-day up to the nearest half day. After your first year, they're free to round up if they choose to, but they don't have to — some employers track holiday down to the exact decimal day instead.
What your employer cannot do
- Give you less than its full-timers' holiday in proportion to your hours, because you work part-time (ACAS).
- Round a part-day of holiday down, at any point in your employment (ACAS).
- Withhold payment in lieu of statutory leave you've accrued but not taken when you leave — regulation 14 requires it to be paid.
- Deduct pay for holiday you've over-taken unless a payback clause was agreed in your contract or in writing beforehand (ACAS).
- Ignore untaken leave carried forward from an earlier leave year when calculating your final pay — regulation 14(6), in force since 1 January 2024, brings carried-forward leave into the payment-in-lieu calculation too.
Frequently asked questions
How do I calculate pro rata holiday for part-time work?
Multiply the days you work each week by 5.6. For 3 days a week that is 16.8 days a year. If your employer gives full-timers more than the legal minimum, multiply the full-time holiday by your weekly hours and divide by the full-time weekly hours.
Is part-time holiday capped at 28 days?
The statutory cap is 28 days, but a part-timer never reaches it: 4 days a week is 22.4 days and 3 days a week is 16.8 days.
How is pro-rata holiday calculated if I'm joining mid-year?
Count the calendar days from your start date to the end of the leave year, divide by the total days in the leave year, then multiply by your full annual entitlement. For example, starting a 28-day-a-year role on 1 September with 212 days left in a 365-day leave year: 212 ÷ 365 × 28 = 16.26 days, rounded up to 16.5 days.
Is holiday calculated differently when leaving a job?
Yes. If your contract does not set a different sum, leaving uses Working Time Regulations 1998, regulation 14: (A × B) − C, where A is your full entitlement, B is the proportion of the leave year that had expired on your last day, and C is leave already taken. It is not the same sum as joining, because it subtracts leave you've already used.
What if I've taken more holiday than I've accrued when I leave?
Under ACAS guidance, an employer can only deduct the excess from your final pay if that was agreed in your contract or in writing beforehand — a payback clause. Without prior written agreement, they generally cannot claw it back through wage deductions.
How do I calculate pro-rata holiday when my hours change mid-year?
The law does not set a method for this. A fair way is to split the leave year into separate periods at the point your hours changed, calculate a pro-rata entitlement for each period using the pattern that applied during it, then add the results together. Check the method with your employer.
Does UK law require rounding up part days of holiday?
During your first year of employment, ACAS guidance says employers must round part-days up to the nearest half day. After the first year, rounding up becomes optional, though employers can never round down.