Pro rata annual leave, worked out in days and hours
Annual leave and holiday entitlement are the same thing under two names, and the pro rata calculation is identical either way. UK law gives every worker at least 5.6 weeks of paid leave each year. For a full-time worker on 5 days a week that is 28 days. Part-time workers receive the same 5.6 weeks, measured against their own working pattern, using the same fraction as their pay:
Used as an annual leave pro rata calculator, the tool above applies that formula and converts the answer into hours as well, because hours are the fairer measure when your working days are different lengths. Enter your hours per working day and both figures appear together.
The 12.07% method for irregular hours
If you have no fixed hours — agency work, zero-hours contracts, casual shifts, or a part-year contract such as term-time only — a fixed number of days cannot work. For leave years starting on or after 1 April 2024, the law says your holiday builds up as you work, at 12.07% of the hours you have worked in the pay period.
The percentage is not arbitrary. A year has 52 weeks; remove the 5.6 weeks of holiday and 46.4 working weeks remain. Divide the holiday by the working weeks — 5.6 ÷ 46.4 — and you get 0.1207, or 12.07%. For every 100 hours you work, you build up 12.07 hours of paid holiday. Work 500 hours and you have built up 60.35 hours. Your employer may pay this as it builds up (“rolled-up holiday pay”) only where the rules allow it and it is shown clearly on your payslip; otherwise you take the time off and are paid when you take it.
Bank holidays: employers may include bank holidays in the 28-day statutory minimum. Use the switch inside the calculator to see your entitlement both ways. If a bank holiday falls on a day you do not normally work, a fair employer credits that share back to your allowance. The full explanation is in our guide to holiday entitlement for part-time workers.
Your pay fraction and your holiday fraction should be the same number. If you have worked out your salary with the pro rata salary calculator, the same fraction applies here — and if an employer uses a smaller fraction for holiday than for pay, it is reasonable to ask them to show their working.
Bank holidays for part-time workers, worked through
There are 8 bank holidays a year in England and Wales (Scotland has 9 and Northern Ireland 10, with different dates). How they interact with a part-time pattern causes more confusion than the rest of holiday law put together, because contracts handle them in two different ways. Both are lawful; they give the same total, arranged differently.
Approach 1 — bank holidays inside the entitlement. This is the more common arrangement, and the one the calculator's switch is set to when it is on. Your whole entitlement, bank holidays included, is pro rated. A three-day-a-week worker gets 28 × (3 ÷ 5) = 16.8 days in total, of which the bank holiday share is 8 × (3 ÷ 5) = 4.8 days. When a bank holiday falls on your working day, it is booked off and uses some of that 4.8; the remaining 12.0 days are yours to book when you choose. If a bank holiday falls on a day you never work, nothing is deducted — the value stays in your allowance.
Approach 2 — bank holidays on top. Some contracts give the leave and the bank holidays separately: “20 days plus bank holidays”, pro rated to 20 × (3 ÷ 5) = 12.0 days of leave, plus bank holidays off when they fall on your working days. The total is the same 16.8 days if every bank holiday is counted fairly — but under this wording a worker whose days dodge the Mondays can end up with less than their 5.6 weeks, which the employer must then top up. Whichever approach your contract uses, the floor is the same: at least 5.6 of your own working weeks off, paid, every year.
The trap to watch for is the contract that pro rates the leave but treats bank holidays as an unadjusted extra for full-time staff only. That leaves part-time staff short of 5.6 weeks, which is not lawful. If your allowance looks light, work out your total — leave plus your bank holiday share — and compare it with 5.6 × your days per week.
Frequently asked questions
Every UK worker is entitled to at least 5.6 weeks of paid holiday a year, worked out pro rata. If full time is 28 days and you work 3 days a week, you get 28 × (3 ÷ 5) = 16.8 days. In hours, that is 16.8 multiplied by your hours per working day.
Yes, for a full-time worker 28 days (5.6 weeks × 5 days) is the statutory minimum, and employers may count bank holidays inside those 28 days. Part-time workers receive the same 5.6 weeks in proportion to their working pattern.
For irregular-hours and part-year workers, holiday builds up at 12.07% of the hours worked. The figure comes from the 5.6 weeks of holiday divided by the remaining 46.4 working weeks in a year: 5.6 ÷ 46.4 = 12.07%. Work 500 hours and you build up 60.35 hours of paid holiday.
No. The 12.07% accrual method is the statutory method for irregular-hours and part-year workers, for leave years starting on or after 1 April 2024. Part-time staff with fixed hours receive a fixed number of days or hours, calculated pro rata from the full-time entitlement.
No. An employer may round entitlement up, but never down below the statutory minimum. If your calculation gives 16.8 days, you must receive at least 16.8 days — many employers round it to 17.