4 on 4 off shift pattern: the rota, the hours and the rules for 12-hour shifts

02

Hours week by week

Any 7 days of the cycle contain either 3 or 4 shifts, so a Monday-to-Sunday week is 36 or 48 hours. Over the 8 weeks it takes the pattern to come round to the same weekday, a crew has 4 weeks of 48 hours and 4 of 36.

03

The days-then-nights variant: 2 days, 2 nights, 4 off

Instead of fixed day and night crews, every crew works two day shifts (07:00–19:00), then two night shifts (19:00–07:00), then has four days off. The cycle is still 8 days and still averages 42 hours; four crews, each starting two days after the previous one, cover 24/7.

• Nights in a row: 2 instead of 4.
• Day to night: the second day shift ends at 19:00 and the first night starts 24 hours later.
• After the nights, four full days off to recover.
• The UK Health and Safety Executive suggests allowing two nights of full sleep when switching from days to nights; this variant allows one.

04

4-on-2-off and 2-on-4-off compared

• 4-on-2-off: a 6-day cycle, an average of 4.67 shifts a week. On 8-hour shifts that is about 37.3 hours a week; on 12-hour shifts it is 56 — above the 48-hour average allowed in the EU (Directive 2003/88/EC, article 6) and in Great Britain only for workers who have agreed in writing to work more (Working Time Regulations 1998, regulation 4).
• 2-on-4-off: 2.33 shifts a week, 28 hours on 12-hour shifts — a part-time pattern. Covering one 12-hour shift every day needs three people on it.
• 4-on-4-off and 2-2-3 both average 42 hours on 12-hour shifts; 2-2-3 keeps the same weekdays every fortnight and never puts more than 3 shifts in a row.

05

The rules for 12-hour shifts

• Daily rest: at least 11 consecutive hours in every 24 (Directive 2003/88/EC, article 3; Working Time Regulations 1998, regulation 10). Twelve hours off between two 12-hour shifts passes.
• Average week: no more than 48 hours over a reference period of up to four months in the EU (articles 6 and 16), 17 weeks in Great Britain (regulation 4). 4-on-4-off averages 42.
• Breaks: a rest break when the working day is longer than six hours (Directive, article 4); in Great Britain at least 20 uninterrupted minutes (regulation 12).
• Night workers: normal hours must not exceed an average of 8 in every 24 (Directive, article 8; regulation 6). A night crew on 4-on-4-off works 336 hours in 56 days; leaving out the 8 weekly rest days, as the rules require, that is an average of 7 in 24.
• Hazardous or heavy night work: no more than 8 hours in any 24-hour period with night work (Directive, article 8(b); regulation 6(7)) — 12-hour nights are not allowed for it.
• The HSE suggests limiting long shifts and night shifts to 2–3 in a row and shifts to 12 hours including overtime. Four 12-hour shifts in a row go beyond that advice; the days-then-nights variant stays within it.

06

In Greece

Working hours may not exceed 8 a day and 48 a week (Labour Code, article 187). Longer shifts are allowed only where the work, by its nature, must run continuously with crews relieving each other, with an average of no more than 48 hours a week; the order of the crews must change every week so that the crew on nights one week works days the next, and anyone who works a Sunday gets 24 hours of rest on another day of that week (article 201).

07

Setting it up in 365shift

• 365shift has no 4-on-4-off generator, and because the cycle is 8 days a one-week template will not repeat it. Build the 8 weeks in which the cycle and the calendar line up, then copy that range (custom view) and paste it, with or without the same people.
• The minimum-rest rule (11 hours by default) warns on any shift that leaves less rest than that.
• The maximum-weekly-hours rule counts Monday to Sunday and blocks shifts above the cap; on this pattern a week can reach 48 hours.