3 on 3 off calculator
Three days on, three days off. Give it the date of your first shift and it returns the whole month: working days, total hours, night hours and pay. Free, no sign-up.
Rota settings
Working shifts
16
per month
Total hours
192 h
192 day, 0 night
Night hours
0 h
within the night window
Weekend hours
60 h
Saturday and Sunday
Base pay, £
£2,496
hours × rate
Premiums, £
£0
night + weekend
Estimated total pay
£2,496
Shift calendar
Working days on 3 on 3 off in the selected month
How the 3 on 3 off pattern works
You work three days, then take three days off, and the cycle repeats every six days. Six does not divide into seven, so the rota drifts across the week: the Monday you work this cycle is a Monday you have off three cycles later. It takes six weeks (42 days, the first point where a six-day cycle and a seven-day week line up again) for your shifts to land on the same weekdays as they do today.
That drift is the reason the pattern is hard to hold in your head, and the reason no two months look alike. The cycle hangs on a single date: the first day of a block of three. Set it above and the calendar below fills in every shift for the month you picked.
How many hours does 3 on 3 off give you
Over a full six-day cycle you work three shifts. On 12-hour shifts that is 36 hours per cycle, which averages 42 hours per week (36 divided by 6, times 7). Across a year it comes to roughly 2,190 hours, or about 182 shifts. On 8-hour shifts the same pattern averages 28 hours a week.
No individual month sits on that average. Depending on where your blocks fall, a calendar month holds between 13 and 16 shifts, so monthly pay moves around even though nothing about the rota has changed. The month above is counted shift by shift, not averaged.
Weekends on a 3 on 3 off rota
The pattern takes no notice of the weekend, so it hands you some and takes others. Over the full six-week cycle the split is exactly even: you work three Saturdays out of six and three Sundays out of six, and the same goes for every other weekday. Which ones you lose this month is the part that matters, and the calendar above marks them before you commit to anything.
Living with three-day blocks
Three in a row is the shortest of the common round-the-clock blocks, and that is its main argument: three nights are easier to come back from than four or seven, and the rest period after them is long enough to be useful rather than just a recovery day. The price is the drift. Your days off move through the week, so anything on a fixed weekly slot (a class, a club, a standing appointment) will collide with the rota every few cycles. It is common wherever cover has to run 24 hours with four crews: care homes, security, control rooms, emergency services and hospitality.
Frequently asked questions
How many hours a week is 3 on 3 off?+
On 12-hour shifts it averages 42 hours a week. You work 36 hours inside each six-day cycle, which spreads to 42 across a seven-day week. On 8-hour shifts the same pattern averages 28 hours.
How many days a year do you work on 3 on 3 off?+
About 182 shifts a year: 365 days divided by the six-day cycle gives roughly 60.8 cycles, and you work three days in each. On 12-hour shifts that is around 2,190 hours.
Does 3 on 3 off break the 48-hour week?+
Normally no. The Working Time Regulations cap the average at 48 hours a week measured over a 17-week reference period, and 12-hour shifts on this pattern average 42. Overtime and covering someone else's block are what push you towards the cap. Check the current rules on gov.uk and read your own contract before relying on that.
Is 3 on 3 off better than 4 on 4 off?+
They pay the same over a year: both average 42 hours a week on 12-hour shifts and both work out at roughly 182 shifts. The difference is how the time is packaged. 3 on 3 off gives shorter blocks and shorter breaks, and it realigns with the week every six weeks; 4 on 4 off gives longer runs of both and takes eight weeks to come back round. Shorter blocks are usually easier on sleep, longer breaks are better for getting away.
How much holiday do you get on 3 on 3 off?+
Statutory holiday in the UK is 5.6 weeks. On a fixed 3 on 3 off pattern that is usually taken in shifts rather than days: 5.6 times your average shifts per week. If your hours are irregular or you are on a zero-hours contract, holiday is instead accrued at 12.07% of the hours you actually work. Check the current rules on gov.uk, and your contract, before you count on a number.
Do you get paid extra for night shifts on 3 on 3 off?+
Only if your contract says so. UK law sets no night premium, which is why this calculator starts at zero. Plenty of employers do pay an unsocial hours uplift; put your own percentage into the form and the night hours will be priced with it.
For managers: run the rota, not the maths
Build next week in the browser: add the team, click the grid, download it. No sign-up.
Start, finish and break per day: hours for the week, overtime and pay at your rate.
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The rota you published becomes the timesheet: hours per person, ready for payroll.