Part-Time Workers: Your Holiday Rights

The pro-rata rule

Part-time workers are entitled to the same 5.6-week minimum holiday as full-time workers, calculated on a pro-rata basis — in proportion to the hours or days they work. This is not optional; it is a legal requirement under the Working Time Regulations 1998.

The pro-rata calculation is:

(Your weekly hours ÷ Full-time hours) × 28 days = Your entitlement

Or using days:

(Days you work per week ÷ 5) × 28 = Your entitlement

Worked examples

Example 1 — 3 days a week, full-time is 5 days:

(3 ÷ 5) × 28 = 16.8 days. Employers should not round in a way that leaves a worker with less than statutory entitlement. Many employers round up to a workable unit (for example, half-days) in policy and payroll systems.

Example 2 — 20 hours a week, full-time is 40 hours:

(20 ÷ 40) × 28 = 14 days. Your entitlement is at minimum 14 days. If your employer calculates this as 20/40 × 5.6 = 2.8 weeks = 14 days, that is correct.

Example 3 — job-share, 2.5 days a week:

(2.5 ÷ 5) × 28 = 14 days. Even a job-share worker doing half a full-time week is entitled to 14 days' minimum holiday.

Bank holidays and part-time workers

Bank holidays can trip up part-time workers more than full-time ones. If a bank holiday falls on a day you would normally work, you are entitled to a day's holiday — or pay in lieu if your employer cannot give you the day off.

If your employer gives all staff the same number of bank holidays off (e.g. 8 days for everyone), part-time workers on fewer days may be disadvantaged. There are two correct approaches:

• Give a substitute day: if a bank holiday falls on a day you don't work, give you a substitute day off in lieu
• Pro-rata bank holidays: give you a proportion of bank holiday entitlement based on your hours

If your employer does neither and you lose bank holiday entitlement as a result, they may be underpaying your statutory minimum.

Common employer mistakes

• Giving full-time holiday rate regardless of hours — a part-time worker doing 2.5 days a week is not entitled to 28 days; the employer may be over-paying (not illegal but worth being aware of)
• Giving the same number of days as full-time workers — e.g. giving a 3-day-a-week worker 28 days is generous but not legally required; giving them 12 days would be under the minimum
• Rounding entitlement down in a way that under-delivers statutory leave — policies should avoid reducing workers below their calculated minimum entitlement
• Excluding bank holidays from the calculation incorrectly — if the contract says "28 days including bank holidays" for a 3-day-a-week worker, that means 3/5 × 28 = 16.8 days total including any bank holidays that fall on working days. If this results in fewer than 3 actual days of base holiday, that may be wrong

What to do if you think your employer is wrong

1. Calculate it yourself using our calculator — enter your hours and days and see what your pro-rata entitlement should be
2. Check your contract — look for the holiday clause and whether it references "statutory minimum" or a specific number of days
3. Speak to your employer or HR — there may be a genuine misunderstanding. Put your calculation in writing and ask them to confirm
4. Contact ACAS — free, confidential advice on 0300 123 1100
5. Citizens Advice — can help you write a formal letter to your employer

If the underpayment is ongoing, you have up to 3 months less a day from the underpayment to bring a claim at the employment tribunal for unlawful deduction from wages.