Worked example: 7 × 12h shifts: 2 posts, 20% unavailable
7 shifts × 12 hours × 2 concurrent posts = 168 coverage hours/week. Each 40h employee contributes 40 × (1 − 20/100) = 32 available hours. 168 ÷ 32 = 5.25 FTE, rounded up to 6 whole people.
Twelve-hour shifts require separate checks for rest, fatigue and break relief. A smaller number of handovers does not reduce the required weekly coverage hours. Both posts need to be filled at the same time; one person cannot fill both simultaneously.
Assumptions and limits
- Shifts/week is per post; hours/shift means required coverage time, not necessarily paid hours.
- Unavailability is an assumed share of contracted hours lost to leave, training or other duties. Do not deduct the same absence twice.
- People are rounded up only after dividing total hours by available capacity. Role matching, handovers, rest and break relief need a separate roster check.
- No payroll, overtime or legal compliance guarantee is made.
Use the full calculator
Shift Coverage Calculator · All free calculators · Calculation methodology
Related guides: Workforce and FTE guides