Is a 3-person 24/7 schedule legal in the EU?

Not for regular active work. A 24/7 operation needs 168 coverage hours per week, which comes to 56 hours per person across 3 people, and the EU Working Time Directive caps average weekly hours at 48. The exception is special duty-based regimes such as fire services, where crews on 24-hour shifts rest at the station and the Kelly 24-on-48-off model is established practice.

What is the Kelly schedule (24-on-48-off)?

The Kelly schedule runs 3 platoons on 24-hour shifts in a repeating 9-day cycle: 24 hours on duty followed by 48 hours off. Each platoon averages 56 hours per week. It is the standard fire-service pattern because the work is response-based and crews can sleep at the station between calls.

How many hours would each of 3 people work on a 24/7 roster?

A 24/7 operation requires 168 hours of coverage per week. Divided across 3 people, that is 56 hours per person per week, with nothing left over for vacation, sickness, or training cover. For comparison, the EU Working Time Directive caps average weekly hours at 48.

What is the minimum headcount for a normal 24/7 schedule?

Four people is the practical minimum, with each averaging 42 hours per week to cover the 168 weekly hours. Five people brings the average down to 33.6 hours and adds the slack needed to absorb leave and sick days. Three people only works in duty-based operations like fire services running the Kelly 24-on-48-off model at 56 hours per week.

Can 3 people run 24/7 monitoring, production, or care work?

No. In those operations every hour on shift is active work, so a 24-hour duty shift becomes 24 hours of labor and each of the 3 people carries 56 hours per week. That exceeds the EU 48-hour average cap and is not sustainable in any jurisdiction. Plan the roster around 4 people at 42 hours each or 5 people at 33.6 hours each.

All staffing scenarios

Staffing math

Can 3 people cover a 24/7 schedule?

168 hours a week across 3 people is 56 hours each, which only works in duty-based services like fire brigades.

The short answer

3 people can only cover 24/7 by splitting 168 weekly coverage hours into 56 hours per person per week, which exceeds the 48-hour legal ceiling most countries apply.

Coverage window: 24/7
Hours to staff / week: 168
Shift length: 24h
Shifts to fill / week: 7
Hours each: 56h
With absence buffer: 6 people

Why the math lands there

Continuous cover comes to 168 staffed hours a week, however you cut it. Split across 3 people, that is 56 hours per person, every single week, before anyone takes a vacation day or calls in sick. The EU Working Time Directive caps average weekly hours at 48, so a 3-person roster for continuous work is over the legal limit in the EU from the first week. For active around-the-clock work, the honest answer is no.

There is one established exception. Fire services cover 24/7 with 3 platoons on the Kelly schedule: 24-hour shifts, 24 on and 48 off, in a 9-day cycle that averages 56 hours per week. It works because the job is response-based. Crews eat, train, and sleep at the station, and special duty-based working time regimes account for those resting hours. Kelly is a duty roster, not 56 hours of continuous labor.

If your overnight hours involve real work, watching screens, running a line, caring for residents, the math forces a hire. A 4th person brings everyone to 42 hours per week, the level the standard 4-team 24/7 rotations are built on. A 5th person brings the average to 33.6 hours and adds room to absorb absence. Below, the pattern that makes 3 work in duty-based services, and the reality check for everyone else.

124 hours a day times 7 days a week = 168 coverage hours to staff every week.
2168 hours divided into 24-hour shifts = 7 shifts to fill every week.
3168 hours divided by 3 people = an average of 56 hours per person per week, or 2.3 shifts each.
4Nobody works every scheduled week. With a typical 20 to 25 percent allowance for leave, sickness, and training, plan for 6 people to keep the roster from running on overtime.

Headcount options, side by side

The same 168 weekly coverage hours spread over different team sizes. Average weekly hours per person is the number that decides whether a roster is sustainable, legal, and affordable.

People	Hours / person / week	Shifts / person / week	Verdict
3this page	56	2.3	Over legal limits in most countries
4	42	1.8	Built-in overtime
5	33.6	1.4	Standard workload
6	28	1.2	Slack for absence
7	24	1	Slack for absence
8	21	0.9	Slack for absence

The absence buffer above assumes 20 to 25 percent of paid time goes to leave, sickness, and training. Your own rate decides the real number, which you can work out with our shrinkage calculator.

Rotations that make this work

These are proven patterns for this configuration, each with a full interactive calendar and staffing breakdown.

Kelly schedule

Kelly is the one established 3-person answer to 24/7: 3 platoons on 24-hour shifts in a 9-day cycle, 24 on and 48 off, averaging 56 hours per week. It holds only where crews can rest during the shift, which is why it has stayed a fire-service pattern.

24h shifts · 3 teams · avg 56h/week

View the full rotation →

What the arithmetic does not tell you

The line between duty and active work is the whole decision. A firefighter can sleep through part of a 24-hour shift because the alarm decides when work happens. A monitoring analyst, a machine operator, or a night caregiver cannot; every hour on site is an hour of work. If that describes your operation, a 24-hour shift is 24 hours of labor, and 56 hours of labor per week breaks people regardless of what any special regime permits.

Three people also means zero relief. Fire departments absorb absence inside the platoon because a platoon is a crew, not one individual. If your roster is literally three individuals, a single vacation or sick day collapses the pattern, and the two who remain are alternating around the clock with no scheduled day off until the third comes back. That failure mode arrives in the first month, not the first year.

If you are sizing a control room, a production line, or a care facility, treat 3 as bridge headcount at most. The 4th hire takes everyone to 42 hours and opens up the standard 4-team rotations. The 5th takes the average to 33.6 hours, which is the point where vacations and sick days become routine events instead of coverage crises. The arithmetic on this page is not a schedule to aim for. It is the case for the next requisition.

Once the headcount is settled, the daily work is keeping the roster fair and covered as people swap, call in sick, and take leave. That is the part Soon automates, from constraint-aware auto-scheduling to leave management.

Frequently asked questions

Is a 3-person 24/7 schedule legal in the EU?: Not for regular active work. A 24/7 operation needs 168 coverage hours per week, which comes to 56 hours per person across 3 people, and the EU Working Time Directive caps average weekly hours at 48. The exception is special duty-based regimes such as fire services, where crews on 24-hour shifts rest at the station and the Kelly 24-on-48-off model is established practice.
What is the Kelly schedule (24-on-48-off)?: The Kelly schedule runs 3 platoons on 24-hour shifts in a repeating 9-day cycle: 24 hours on duty followed by 48 hours off. Each platoon averages 56 hours per week. It is the standard fire-service pattern because the work is response-based and crews can sleep at the station between calls.
How many hours would each of 3 people work on a 24/7 roster?: A 24/7 operation requires 168 hours of coverage per week. Divided across 3 people, that is 56 hours per person per week, with nothing left over for vacation, sickness, or training cover. For comparison, the EU Working Time Directive caps average weekly hours at 48.
What is the minimum headcount for a normal 24/7 schedule?: Four people is the practical minimum, with each averaging 42 hours per week to cover the 168 weekly hours. Five people brings the average down to 33.6 hours and adds the slack needed to absorb leave and sick days. Three people only works in duty-based operations like fire services running the Kelly 24-on-48-off model at 56 hours per week.
Can 3 people run 24/7 monitoring, production, or care work?: No. In those operations every hour on shift is active work, so a 24-hour duty shift becomes 24 hours of labor and each of the 3 people carries 56 hours per week. That exceeds the EU 48-hour average cap and is not sustainable in any jurisdiction. Plan the roster around 4 people at 42 hours each or 5 people at 33.6 hours each.

Can 2 people cover a 24/7 schedule?

Splitting 168 coverage hours two ways is 84 hours per person per week, so this page is about the exits, not a rotation grid.

168 hours/week · 12h shifts

See the math →

What is the best 24/7 shift pattern for 4 people?

Four people at 42 hours each is the classic small-team 24/7 staffing level, and the pattern choice matters more than the headcount math.

168 hours/week · 12h shifts

See the math →

How many employees do you need to cover 24/7 with 8-hour shifts?

168 hours a week divided into 21 eight-hour shifts is 4.2 FTE, and that fraction is the whole problem.

168 hours/week · 8h shifts

See the math →