How many employees do you need to cover 24/5 with 12-hour shifts?
120 coverage hours, 10 twelve-hour shifts, exactly 3.0 FTE, and a week that refuses to split evenly.
The short answer
Covering 24 hours a day, 5 days a week with one person on duty means staffing 120 hours a week: a minimum of 3 employees at 40 hours each, and realistically 4 once holidays, sickness, and training are priced in.
- Coverage window
- 24 hours a day, 5 days a week
- Hours to staff / week
- 120
- Shift length
- 12h
- Shifts to fill / week
- 10
- Bare minimum
- 3 people
- With absence buffer
- 4 people
Why the math lands there
Twenty-four hours a day, Monday through Friday, with one person on duty adds up to 120 coverage hours a week. Twelve-hour shifts split each day into a day shift and a night shift, so the week is 10 shifts. That 120 hours is exactly three 40-hour workloads, 3.0 FTE on the nose. The minimum roster is 3 people averaging exactly 40 hours each, and the realistic roster is 4.
The alternatives do not work well. Two people means 60 hours each, which is over legal limits. Four people means 30 hours each, 2.5 shifts per person per week, so you are either running part-timers or paying for slack. And even the clean-looking 3-person option hides a wrinkle: 40 hours does not divide into 12-hour shifts, so nobody actually works a 40-hour week. People alternate 3-shift weeks of 36 hours and 4-shift weeks of 48 hours.
What you buy with this configuration is weekends. Unlike any 24/7 roster, everyone here is off Saturday and Sunday every week, with no rotation games and no premium pay for weekend shifts. For an operation that only runs on weekdays, that is a real retention advantage, and it is the main reason to accept the messier weekday arithmetic instead of moving to a four-team 24/7 pattern.
- 124 hours a day times 5 days a week = 120 coverage hours to staff every week.
- 2120 hours divided into 12-hour shifts = 10 shifts to fill every week.
- 3120 hours divided by a 40-hour workweek = 3 full-time equivalents, so 3 employees minimum.
- 4Nobody works every scheduled week. With a typical 20 to 25 percent allowance for leave, sickness, and training, plan for 4 people to keep the roster from running on overtime.
Headcount options, side by side
The same 120 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 |
|---|---|---|---|
| 1 | 120 | 10 | Not viable |
| 2 | 60 | 5 | Over legal limits in most countries |
| 3this page | 40 | 3.3 | Standard workload |
| 4 | 30 | 2.5 | Slack for absence |
| 5 | 24 | 2 | Slack for absence |
| 6 | 20 | 1.7 | 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.
What the arithmetic does not tell you
The 3-4 alternation is more bookkeeping than it looks. Ten shifts split three ways is 4 plus 3 plus 3, so every week one person carries a 48-hour week while the other two work 36. Over a three-week cycle each person takes the heavy week once, but one vacation or public holiday breaks the rotation, and now someone is owed a light week that both payroll and the schedule have to remember.
Decide up front how pay works. If everyone is salaried at 40 hours, the alternation is invisible in payroll but very visible to the person on their fourth 12-hour shift of the week. If you pay hourly, check how your rules treat the 48-hour weeks before you commit, because a schedule that averages 40 can still generate weekly overtime cost depending on your contracts. The same coverage with 8-hour shifts divides evenly and avoids this, at the price of a third handover every day.
Also settle where the week starts and ends. A 24/5 week on 12-hour shifts is not Monday 9 to Friday 5. If nights run 18:00 to 06:00, either someone clocks in on Sunday evening or your coverage week runs Monday 06:00 to Saturday 06:00. And with 3 people there is no dedicated night worker: everyone rotates through the 5 night shifts, and the EU requirement of 11 hours of daily rest rules out moving straight from a night shift onto the following day shift.
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
- How many employees do you need to cover 24/5 with 12-hour shifts?
- Three employees is the floor, and 4 is the realistic roster. Coverage of 24 hours a day, Monday through Friday, with one person on duty adds up to 120 hours a week, or 10 twelve-hour shifts. Against a 40-hour target week that is exactly 3.0 FTE, so 3 people covers it on paper and a fourth gives you room for sick days and vacation.
- Can 3 people cover 24/5 on 12-hour shifts?
- Yes, 3 people can cover it at an average of exactly 40 hours each, but the roster has zero slack and nobody works an identical week. Because 40 hours does not divide into 12-hour shifts, people alternate 3-shift weeks of 36 hours and 4-shift weeks of 48 hours. Any absence has to be absorbed by the other two.
- Why does nobody work a normal 40-hour week on this schedule?
- Because 40 is not a multiple of 12. The week contains 10 twelve-hour shifts, and 10 shifts split across 3 people is 4 for one person and 3 for the other two, which is a 48-hour week next to two 36-hour weeks. Rotating who takes the 4-shift week keeps everyone at a 40-hour average, but no single week is actually 40 hours.
- Is the 48-hour week in this rotation legal?
- In the EU, the Working Time Directive caps average weekly hours at 48, so a single 48-hour week inside a rotation that averages 40 hours sits within the cap. The EU also requires 11 hours of daily rest between shifts, which a 12-hour pattern can respect as long as you never schedule a day shift directly after a night shift. Confirm against your own contracts and local rules on top of that.
- Do employees get weekends off on a 24/5 schedule with 12-hour shifts?
- Yes, and that is the main advantage over 24/7 coverage. All 10 shifts fall Monday through Friday, so every person on the roster is off both Saturday and Sunday, every week. The one decision left is where the week boundary sits, since a night shift that starts at 18:00 on Friday ends at 06:00 on Saturday.
Adjacent staffing questions
How many employees do you need to cover 24/5 with 8-hour shifts?
Three people at exactly 40 hours each fits the math perfectly, and a fourth is what keeps it working.
120 hours/week · 8h shifts
See the math →How many employees do you need to cover 24/7 with 12-hour shifts?
The math says 4.2 FTE and a minimum of 5 people, but the whole industry runs this on 4 people at 42 hours.
168 hours/week · 12h shifts
See the math →How many people do you need to cover 12 hours a day, 7 days a week with 12-hour shifts?
One 12-hour shift per day, seven days a week: 84 coverage hours, 2.1 FTE, and a straight choice between 2 people at 42 hours or 3 at 28.
84 hours/week · 12h shifts
See the math →Your next schedule could take 2 minutes.
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