Staffing calculator: how many staff do you need?
Estimate the headcount needed to cover every shift. Enter your opening hours, how many people must be on at once, and each employee’s contracted hours.
Estimate only — real needs vary with peaks, breaks and skill mix. Use it as a starting point.
Know the number — now build the fair roster that delivers it.
Plan coverage with RosternaHow the staffing calculator works
It counts the hours that need covering each week, divides them by the hours one employee works, adds a buffer for absence, and rounds up. With the starting values (open 12 hours a day, 7 days a week, 2 people on at once, 40 contracted hours, a 15% buffer), the steps are:
| Step | Calculation | Result |
|---|---|---|
| Weekly coverage hours | 12 hours × 7 days × 2 at once | 168 hours |
| People before the buffer | 168 ÷ 40 contracted hours | 4.2 |
| With a 15% absence buffer | 4.2 × 1.15 | 4.83 |
| Staff needed | Rounded up | 5 people |
Which weekly hours to enter in Saudi Arabia
Enter the hours in the employment contract. The Labour Law sets the ceiling: no more than 8 actual hours a day under the daily standard, or 48 a week under the weekly standard, and in Ramadan no more than 6 a day or 36 a week for Muslim workers (Article 98). Breaks are not working hours (Article 102), so use hours actually worked, not hours on site.
The same shop as above, open 12 hours a day with 2 people on at once, needs a different headcount at each figure:
| Hours per employee / week | Before buffer | With 15% buffer | Staff needed |
|---|---|---|---|
| 40 | 4.2 | 4.83 | 5 |
| 48 (weekly limit, Article 98) | 3.5 | 4.03 | 5 |
| 36 (Ramadan limit for Muslim workers, Article 98) | 4.67 | 5.37 | 6 |
Choosing the absence buffer
The buffer is spare capacity for the days people are away. Annual leave alone is at least 21 days a year, and at least 30 after five continuous years with the same employer (Article 109), which is roughly 6 to 8% of the year. Sick days, Eid holidays (Article 112) and staff leaving add to it.
Our reading, not a rule: 10 to 20% is a sensible starting point, and your own records of last year's absence are a better guide than any default.
Why the result is an estimate
The calculator assumes the same number of people all day. Real demand has peaks, and some shifts need a specific skill, a supervisor or a woman on duty. It also cannot see how shift lengths fit together: 168 weekly hours split into 12-hour shifts behaves differently from 8-hour shifts. Use the number to size the team, then build the roster against your real hourly needs.
From headcount to a roster
In Rosterna you set how many people you need on each day and shift, and the engine builds the monthly roster around those needs, your rest rules, fairness and staff preferences. You can still edit any shift by hand.
Sources
Checked against the official text on . This is a general explanation, not legal advice. The official text is the reference and can change.
Frequently asked questions
How many staff do I need to cover one position 24/7?
One position around the clock is 24 × 7 = 168 hours a week. At the 48-hour weekly limit that is 3.5 people, so at least 4 just to cover the hours (4 people × 42 hours), and 5 once you add a 15% buffer for leave and sickness.
What weekly hours should I use?
The hours in the employment contract. Article 98 sets the ceiling at 48 actual hours a week under the weekly standard, and 36 in Ramadan for Muslim workers.
Do I need more staff in Ramadan?
Often, yes, if your opening hours stay the same. Muslim workers' hours drop to no more than 36 a week (Article 98), so the same 168 coverage hours need 4.67 people instead of 3.5 before any buffer.