Guide
Shift pattern meaning: 4 on 4 off, continental, Panama and DuPont
Updated
Shift pattern names are trade shorthand rather than standards, and several of them describe the same cycle. Knowing which is which saves a lot of time in a consultation, because two patterns with different names and identical arithmetic will produce identical objections.
Talk to a specialist Three numbers in, and you have the cycle, the average week, the crews and the Working Time position.
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How this calculator works
- The 48 hour average weekly limit is applied as gov.uk states it: "you cannot work more than 48 hours a week on average, normally averaged over 17 weeks". A worker may choose to opt out of the 48 hour week in writing, and several categories of work sit outside the limit entirely, including jobs requiring 24 hour staffing, the armed forces and emergency services, and roles where working time is not measured and the worker controls their own decisions (gov.uk).
- Average weekly hours are computed from the SHAPE of the cycle rather than from a calendar: days on divided by cycle length, times seven, times the shift length. That is exact for a repeating cycle and is why a 4 on 4 off 12 hour pattern produces 42 hours a week rather than the 48 people assume from the shift length.
- Daily rest is 11 hours between working days and the weekly rest is either an uninterrupted 24 hours each week or an uninterrupted 48 hours each fortnight. Workers also have the right to one uninterrupted 20 minute rest break during the working day where they work more than 6 hours (gov.uk).
- The daily rest figure assumes shifts on consecutive days start at the same clock time, so the gap is 24 hours minus the shift. A pattern that rotates forward from nights to days inside a cycle can produce a shorter gap than this figure shows, and that transition is the one to check by hand.
- Night workers are staff who regularly work at least 3 hours during the night period, which is 11pm to 6am unless the worker and employer agree a different period. They "must not work more than an average of 8 hours in a 24-hour period", usually calculated over 17 weeks, or up to 52 weeks by agreement. Where the work involves special hazards or heavy physical or mental strain the limit is absolute: they "cannot work longer than 8 hours in any 24-hour period" (gov.uk).
- The crew count is arithmetic, not a rota: shifts needed a day multiplied by the cycle length over the days on. It tells you how many crews the pattern implies for the cover you asked for. It does not account for holiday, sickness, training or the relief factor, all of which push the real headcount above it.
- Under 18s are not modelled. gov.uk states that under 18s "cannot work more than 8 hours a day or 40 hours a week", that 16 and 17 year olds "cannot work between midnight and 4am", and that they usually cannot work between 10pm and 6am, with narrow industry exceptions. Any pattern involving young workers needs checking against those rules directly.
- No figure here is a market rate, a typical pay rate or a benchmark. Everything the tool returns is derived from the pattern you enter and the published statutory limits, and nothing is estimated.
The on-off patterns
4 on 4 off, 3 on 3 off and 7 on 7 off all describe a run of working days followed by an equal run of rest days. All three work half the days in the cycle, so on 12 hour shifts all three average 42 hours a week and all three need four crews for continuous cover.
What separates them is human rather than arithmetic. A three day run is easier to recover from than a seven day one; a seven day run gives whole weeks off. The 4 on 4 off cycle of eight days rotates through the calendar so that weekends fall differently each cycle, which is either the attraction or the objection depending on who you ask.
2-2-3, often called Panama
Two on, two off, three on, then the mirror image in the second week. It is a fourteen day cycle that works seven days in fourteen, so on 12 hour shifts it averages 42 hours a week, the same as the simpler on-off patterns.
The reason it exists is the weekend. Because the cycle is exactly a fortnight, the pattern lands on the same days every two weeks and gives every crew a full weekend off in alternate weeks. That predictability is what people are buying, and it costs nothing in hours.
Continental shifts and DuPont
Continental patterns are the family that rotates crews through mornings, afternoons and nights on short runs, usually on 8 hour shifts, in a cycle of four or eight weeks. They exist to spread the unsocial hours evenly rather than to concentrate them.
DuPont is a four week rotating cycle on 12 hour shifts, built around giving each crew a stretch of seven consecutive days off once a month. It averages 42 hours a week over the full four week cycle, which is the point at which its arithmetic can be checked: measuring a DuPont pattern over a single week tells you nothing.
The name to distrust
Any pattern described only by its shift length. "We run 12 hour shifts" says nothing about the average week, which can be anything from 36 to 60 hours depending on the ratio.
The two numbers that decide everything are days on and cycle length. Ask for those first, and the name becomes a label rather than a claim.