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How many employees do you need to cover your shifts?

Work out how many full-time equivalents (FTE) your shift plan really needs — and how many people that means in practice.

Coverage by day, time and roleFull-time and part-time contractsAnnual leavePublic holidaysSickness absenceTraining and other paid time offOptional safety buffer
1
Which shifts do you need to cover?

Enter each recurring shift with the minimum number of qualified employees who must be working. If your needs differ by day, time, role or location, simply add more rows.

Shift 1
80 h / week
2
What does full-time mean in your organisation?

The paid hours per week a full-time employee works in your organisation.

Used to convert leave and training days into hours.

Used to estimate how many people you actually need — especially if some of your team work part-time.

3
When is your team unavailable?

Nobody works 52 weeks a year. Enter the paid time when your employees are not available to cover shifts.

The average leave entitlement per employee.

Only add them if they are not already counted in annual leave.

Your own historical sickness rate works best here.

Mandatory training and other paid development time.

Things like recurring meetings, admin work or special leave — anything that is paid but does not cover a shift.

4
Want to add a safety buffer?

Extra capacity for unexpected demand or operational surprises.

Don’t put leave or normal sickness in here — they are already counted above.

Staffing you need
2.43FTE

That’s roughly 3 people on an average contract of 36 hours per week.

How the number breaks down
Hours to cover80 h/week
Theoretical minimum (no absences)2 FTE
Real requirement, absences included2.43 FTE
Safety buffer+0 FTE
Recommended requirement2.43 FTE

One full-time employee is available for about 82% of their contracted hours (32.9 of 40 h per week).

And where are you today?
Create your schedule

How the calculation works

First, the calculator adds up all the hours when someone has to be at work:

Hours to cover = shift length × employees needed × shifts per week

Then it estimates how many hours a full-time employee can realistically work once you subtract leave, public holidays, sickness and training.

Productive hours = contracted hours − absences

From that, the staffing requirement follows:

FTE needed = hours to cover ÷ productive hours of one full-time employee

Finally, it estimates how many people that is, based on the average weekly contract in your team.

Example: how many people does a 24/7 operation need?

One position staffed around the clock means:

24 hours × 7 days = 168 hours per week

With 40-hour contracts, the theoretical minimum would be:

168 ÷ 40 = 4.2 FTE

But that assumes nobody ever takes leave, gets sick or attends training. If each employee is realistically available for 85% of their hours:

168 ÷ (40 × 0.85) = 4.94 FTE

A safety buffer pushes the number up further. And since you can’t hire half a person, the final headcount is usually rounded up.

FTE is not the same as headcount

FTE measures working capacity; headcount counts people one by one. A few examples:

  • One employee working 40 hours is exactly 1 FTE (when the full-time week is 40 hours).
  • Two employees on 20 hours each also add up to 1 FTE.
  • Five FTE can require eight or more people if many of them work part-time.

That’s why the calculator shows both: FTE and the estimated number of people.

Does this guarantee the rota will work out?

No. Having enough hours on paper doesn’t mean you can turn them into a workable rota. In practice it can still fall apart because of:

Individual availability
Missing skills
Weekly hour limits
Mandatory rest periods
Too many days in a row
Night-shift restrictions
Fair weekend rotation
Already approved leave
Part-time working patterns

The calculator tells you how much capacity you need. Whether real people can actually be scheduled into real shifts is a job for a scheduling tool.

Frequently asked questions

From a staffing number to a working schedule

Knowing you need 5.4 FTE is just the start. The real question is whether your actual people can cover the shifts — with their availability, leave, skills and rest periods. That’s exactly what Shift Scheduler does: it turns your staffing requirement into a rota that works.