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All staffing scenarios
Staffing math

How many people do you need to cover 16 hours a day, Monday to Friday, with 8-hour shifts?

Two 8-hour shifts a day, five days a week: 80 coverage hours, exactly 2.0 FTE, and no room for a single sick day.

The short answer

Covering 16 hours a day, 5 days a week with one person on duty means staffing 80 hours a week: a minimum of 2 employees at 40 hours each, and realistically 3 once holidays, sickness, and training are priced in.

Coverage window
16 hours a day, 5 days a week
Hours to staff / week
80
Shift length
8h
Shifts to fill / week
10
Bare minimum
2 people
With absence buffer
3 people

Why the math lands there

16 hours a day for five days is 80 coverage hours a week. With one person on duty and 8-hour shifts, each day breaks into an opening shift and a closing shift, 10 shifts a week in total. Eighty hours is two 40-hour workloads exactly, 2.0 FTE with nothing left over. On paper it could not be tidier: one opener, one closer, five days each.

The options are narrow. One person would carry all 80 hours, which is not viable. Two people means 40 hours each, standard full-time with zero slack. Three people means 26.7 hours each, roomy enough that the third role is usually a part-timer or someone shared with another team. There is nothing between two and three, so the real decision is whether you run at exactly 40 hours or buy yourself cover.

This is the smallest real coverage problem in scheduling, and that is what makes it deceptive. Two people at exactly 40 hours is not a small version of a large roster. It is an operation with two single points of failure and nobody to swap with. The rest of this page is about what breaks first and what the third person actually buys you.

  1. 116 hours a day times 5 days a week = 80 coverage hours to staff every week.
  2. 280 hours divided into 8-hour shifts = 10 shifts to fill every week.
  3. 380 hours divided by a 40-hour workweek = 2 full-time equivalents, so 2 employees minimum.
  4. 4Nobody works every scheduled week. With a typical 20 to 25 percent allowance for leave, sickness, and training, plan for 3 people to keep the roster from running on overtime.

Headcount options, side by side

The same 80 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.

PeopleHours / person / weekShifts / person / weekVerdict
18010Not viable
2this page405Standard workload
326.73.3Slack for absence
4202.5Slack for absence
5162Slack 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

With two people at exactly 40 hours, every absence is a coverage failure, not a scheduling puzzle. There is no one to call. When the opener takes a week of vacation, the closer would have to work 80 hours to hold the line, so in practice you shorten opening hours or the manager covers. A single sick day forces the same choice by 06:00 that morning. The arithmetic says 2.0 FTE. The operation needs a named answer for who covers when one of the two is out.

The 16-hour span also blocks the obvious rescue move. If coverage runs 06:00 to 22:00, the closer finishes at 22:00 and the next opening shift starts at 06:00, a gap of 8 hours. In the EU that is below the required 11 hours of daily rest between shifts, so the closer cannot legally open the next morning, and the same math applies to a 07:00 to 23:00 day. Whoever covers a missing opener has to come from outside the two-person pair. That is the concrete case for the third person.

Then there is the early/late split itself. Fixed roles are easier to staff, but one person permanently opens at 06:00 while the other never sees an evening free, and resentment builds along that line. Alternating weeks is fairer and keeps both people able to run either shift, at the cost of a sleep schedule that flips every Monday. The third person does not need to be a full hire to defuse any of this. At three people the average is 26.7 hours, so a part-timer taking two or three shifts a week, or a cross-trained colleague from an adjacent team, turns two single points of failure into a roster.

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 people do you need to cover 16 hours a day, Monday to Friday, with 8-hour shifts?
Covering 16 hours a day for 5 days is 80 coverage hours a week, split into 10 eight-hour shifts, which is exactly 2.0 FTE at a 40-hour target. The minimum is 2 people at exactly 40 hours each, one opening and one closing. A realistic roster is 3 people averaging 26.7 hours each, so absences can be absorbed.
Can 2 people cover a 16/5 schedule on their own?
Yes, at exactly 40 hours each: one works the opening shift and one works the closing shift, Monday to Friday. That leaves zero slack, so any sick day, vacation day, or training day removes coverage with no one available to fill it. Treat 2 as the mathematical minimum and name in advance who covers when one of them is out.
How does a 3-person roster for 16/5 coverage work?
With 3 people sharing 10 shifts a week, each averages 26.7 hours, so nobody is full-time on this coverage alone. The common setup is two full-timers on opening and closing plus a part-timer who takes a few shifts a week and absorbs vacations and sick days. Cross-trained colleagues from another team can fill the third role instead of a new hire.
Can the same person close at night and open the next morning?
Not in the EU without breaking rest rules. A 16-hour day that runs 06:00 to 22:00 leaves only 8 hours between the end of the closing shift and the start of the next opening shift, and the EU Working Time Directive requires 11 hours of daily rest between shifts. The practical consequence is that a missing opener cannot be replaced by the closer, so cover has to come from a third person.
Should the opener and closer roles be fixed or alternate weekly?
Fixed roles are easier to recruit for and give each person a stable routine, but they harden the roster into two positions nobody can swap between. Alternating weeks keeps both people current on both shifts and shares the less popular slot, at the cost of a schedule that flips every week. With only 2 people, alternating has one hidden advantage: both stay able to cover either shift, which matters the moment one of them is absent.

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