Worked example: 4 × 8h shifts: 1 post, 20% unavailable
4 shifts × 8 hours × 1 concurrent post = 32 coverage hours/week. Each 40h employee contributes 40 × (1 − 20/100) = 32 available hours. 32 ÷ 32 = 1 FTE, rounded up to 1 whole people.
A small pool can have enough total hours yet still fail weekend or concentrated-day availability. Match individual availability to each service window. This example covers one concurrent post, not every role in a department.
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