A worker on a 4-day week in the UK is entitled to a statutory minimum of 22.4 days of paid annual leave per year. This comes from the rule that every worker gets 5.6 weeks of leave · multiplied by their 4-day week, that is 22.4 days. Because employers can only round up, this is normally expressed as 22.5 days. The figure can include bank holidays if the contract says so.
The simple answer: 22.4 days
The Working Time Regulations 1998 give every UK worker the right to 5.6 weeks of paid annual leave per year. That rule is set in weeks, not days, on purpose · it works for everyone, full-time or part-time, because it scales with the working week.
For someone who works 4 days a week, 5.6 weeks of leave converts directly into days like this:
That is the statutory floor. An employer can offer more, but never less. We have a complete walk-through of the 5.6 multiplier and how to compute every working pattern in our UK annual leave entitlement guide.
Calculate your entitlement
Use the calculator below to work out a 4-day worker's entitlement, including bank holidays and any enhanced contractual leave the employer offers on top.
How the 5.6 multiplier works
The Acas guidance on holiday entitlement explains the rule plainly: to work out someone's holiday in days, you multiply the number of days they work each week by 5.6. So a 5-day worker gets 28 days, a 4-day worker gets 22.4 days, a 3-day worker gets 16.8 days, and so on.
The 5.6 figure is locked in legislation. It comes from the original 4 weeks of leave under the EU Working Time Directive plus an additional 1.6 weeks added by the UK government in 2007 to absorb the eight bank holidays in England, so the total 5.6 weeks is intended to be enough to cover bank holidays if the employer chooses to count them.
Note that there is a statutory cap of 28 days. Someone working 6 or 7 days a week is still only entitled to a maximum of 28 days, not 33.6 or 39.2.
The rounding rule: up only, never down
22.4 is an awkward number to put into a leave booking system. Most employers express it as 22.5 days. That is fine · and it is required, not optional.
UK employers can only round holiday entitlement up, never down. Rounding 22.4 days down to 22 would breach the Working Time Regulations because the worker has been short-changed by 0.4 of a day. The safe option is 22.5.
An alternative is to track the entitlement in hours rather than days. If the four days are each 7.5 hours long, the worker has a 30-hour week. 30 hours x 5.6 weeks gives 168 hours of annual leave a year · no rounding needed. The worker draws down hours from this pot when they book a day off, matched to the length of the day they would have worked. Many leave-tracking systems handle this neatly without forcing the awkward 22.4 figure.
Bank holidays and the 4-day worker
This is the area that catches most employers out. There is no statutory right to bank holidays for any UK worker · paid time off on bank holidays only happens if the contract grants it. So how the 22.4 figure interacts with bank holidays depends entirely on what the contract says.
There are three common arrangements:
Why bank holidays must be pro-rated for part-timers
The Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 say a part-time worker cannot be treated less favourably than a comparable full-time colleague. If a full-time colleague gets the eight England-Wales bank holidays as paid leave on top of their 28 days (so 36 days total), a 4-day-a-week part-timer must get a pro-rata bank holiday allowance on top.
That is 8 x 4/5 = 6.4 days, normally rounded up to 6.5. The point is that some bank holidays will fall on the part-timer's working days and some on their non-working days. By granting a pro-rata allowance rather than only the bank holidays that actually fall on a working day, the worker gets a fair share regardless of which days they happen to work.
A full-timer gets 25 days plus 8 bank holidays = 33 days total. The pro-rata for a 4-day worker is 25 x 4/5 = 20 days plus 8 x 4/5 = 6.4 days = 26.4 days total, rounded to 26.5. Some firms simplify by giving 26.5 in a single allowance.
When the 4 days are different lengths
The 22.4-days answer assumes each of the four days is the same length. If a worker does, say, 8 hours on Monday, 8 hours on Tuesday, 4 hours on Wednesday, 8 hours on Thursday and is off Friday · working 28 hours over four days · then the day-based calculation is misleading. A "day" of leave on Wednesday gives them 4 hours off, but a "day" of leave on Tuesday gives them 8 hours off.
GOV.UK guidance suggests calculating in hours instead. The maths is the same 5.6 multiplier:
The worker has 156.8 hours of annual leave (rounded up to 157). When they take a day off, the hours of that specific day are deducted from the pot. A Wednesday off costs 4 hours, a Tuesday off costs 8.
Joining or leaving mid-year on a 4-day week
For a regular-hours 4-day worker who joins or leaves mid-year, the entitlement is pro-rated by the proportion of the leave year worked. GOV.UK allows two methods:
Take the full annual entitlement (22.4 days) and multiply it by the fraction of the leave year worked. Joining six months in gives 22.4 x 6/12 = 11.2 days, rounded up to 11.5.
An employer can give one-twelfth of the annual entitlement for each calendar month worked. So someone joining in July (with six months remaining in a January-December leave year) accrues 22.4 / 12 x 6 = 11.2 days. Either method gets to a similar answer for a regular-hours worker.
Whichever method you use, round the final figure up to the nearest half day in the worker's favour. The worker accrues from day one · GOV.UK confirms accrual cannot be delayed for any kind of probation period.
For more detail on joiners specifically, including the GOV.UK two-tier rounding (1/12 per month, then half-day on each pay period), see our holiday entitlement for new starters guide.
When the employer offers more than statutory
Many UK SMEs offer above the statutory 5.6 weeks. A 4-day worker on an enhanced contract gets the same proportional uplift.
| Full-time allowance | Weeks | 4-day pro-rata | Rounded up |
|---|---|---|---|
| 28 days (statutory) | 5.6 | 22.4 days | 22.5 |
| 30 days | 6.0 | 24.0 days | 24.0 |
| 33 days | 6.6 | 26.4 days | 26.5 |
| 36 days (28 + 8 BH) | 7.2 | 28.8 days | 29.0 |
| 40 days | 8.0 | 32.0 days | 32.0 |
There is no rule that enhanced leave must scale exactly pro-rata. Some employers cap part-time leave at the same number of days as full-time, which works against part-timers. The Part-Time Workers Regulations require parity, so this kind of cap is risky unless the contract is structured very carefully.
Common mistakes to avoid
22.4 must round to 22.5 or stay at 22.4. Rounding to 22 short-changes the worker by 0.4 days every year, which is a Working Time Regulations breach.
If full-timers get bank holidays on top, part-timers must get a pro-rata bank holiday allowance on top · not just the ones that happen to fall on their working days. Otherwise the worker is treated less favourably depending on which days of the week they happen to work.
A "day" off only means the same thing if every day is the same length. Where days vary, calculate in hours. Multiply weekly hours by 5.6 and track the leave pot in hours rather than half-days.
The cleanest way to handle a mix of full-time, 4-day and 3-day workers is to set the right allowance for each person individually rather than try to compute it on the fly each time someone books leave. We have a wider walk-through of part-time holiday entitlement for the full picture.
Sources
| Working Time Regulations 1998 | Regulations 13 and 13A · statutory annual leave entitlement |
| GOV.UK | Calculate holiday entitlement |
| GOV.UK | Holiday entitlement: rights and rules |
| GOV.UK | Official holiday entitlement calculator |
| Acas | Holiday entitlement guidance |
| Part-Time Workers Regulations 2000 | Less favourable treatment of part-time workers |
| nidirect | Holiday entitlements (Northern Ireland) |
Frequently asked questions
How many days holiday is someone working 4 days a week entitled to in the UK?
Under the Working Time Regulations 1998, a worker on a 4-day week is entitled to a statutory minimum of 22.4 days paid annual leave per year (5.6 weeks multiplied by 4 days). Employers must round any entitlement up · never down · so this is usually expressed as 22.5 days. This figure can include bank holidays if the contract says so, or be granted on top.
Should a 4-day-a-week worker get 22.4 or 22.5 days holiday?
The statutory floor is 22.4 days (5.6 x 4). UK employers cannot round down, so most round up to 22.5 days for ease of booking. The 22.4 figure is also valid · it can be tracked in hours instead of half-days, which is what payroll systems often do for part-timers with non-standard daily hours.
Do part-time workers on a 4-day week still get bank holidays?
There is no statutory right to bank holidays for any UK worker · they are only paid days off if the contract says so. If a full-time colleague is given the eight bank holidays in England as paid leave on top of their entitlement, a 4-day-a-week part-timer must receive a pro-rata bank holiday allowance to comply with the Part-Time Workers Regulations 2000. That is 6.4 days (8 x 4/5), often rounded up to 6.5.
What if someone works 4 days a week but their daily hours vary?
Where a worker has fixed hours but varying lengths of day, GOV.UK recommends calculating their leave entitlement in hours rather than days. Take the total weekly hours, multiply by 5.6, and you have their annual leave in hours. For example, someone working 30 hours over four days is entitled to 168 hours of annual leave (30 x 5.6). They draw down hours when they take leave, matched to whatever shift they would have worked.
What about a 4-day week for a mid-year starter?
For someone joining mid-year on a 4-day week, take their full annual entitlement (22.4 days) and pro-rata it by the proportion of the leave year remaining. So joining halfway through the year gives 11.2 days. GOV.UK and ACAS allow employers to use either the proportion-of-year method or a 1/12-per-month accrual method · both reach a similar answer for a regular-hours starter.
Can an employer offer a 4-day worker fewer than 22.4 days holiday?
No. 22.4 days is the statutory floor for a 4-day-a-week worker. Offering less breaches the Working Time Regulations 1998 and the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000. Employers can offer more (many do) and can include bank holidays within the figure · but they cannot offer less than the pro-rata statutory minimum.
This guide is for general information and is not legal advice. For guidance on a specific situation, contact the Acas helpline on 0300 123 1100 or speak to an employment solicitor.