# Workforce Scheduling Coverage Calculator

> Check whether your roster covers opening hours at minimum staffing after shrinkage, and how many staff you need to cover them fully.

Category: Salary, HR & payroll · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/workforce-scheduling-coverage-calculator

Coverage compares the staff-hours you need on the floor with the hours your roster actually delivers after absence, training and other shrinkage.

Also called: Staffing calculator, Shift coverage calculator.

## Inputs
- Hours open per day (unit h; default 12)
- Days open per week (unit days; default 7)
- Staff needed on duty at all times (unit people; default 3)
- Staff on the roster (unit people; default 8)
- Shifts per person per week (default 5)
- Hours per shift on duty (unit h; default 8)
- Shrinkage (absence, training, leave) (unit %; default 15; optional)

## Results
- Coverage
- Staff-hours needed per week
- Staff-hours delivered per week
- Surplus (+) or shortfall (−)
- Staff needed for full coverage

## Formula

```
Needed = Hours open × Days open × Minimum staff;  Delivered = Staff × Shifts × Shift hours × (1 − Shrinkage);  Coverage = Delivered ÷ Needed × 100;  Staff needed = ⌈Needed ÷ (Shifts × Shift hours × (1 − Shrinkage))⌉
```

Where:
- Shrinkage: share of rostered time lost to leave, sickness, training and breaks

## Worked example
1. Needed = 12 × 7 × 3 = 252 staff-hours a week.
2. Each person delivers 5 × 8 × 0.85 = 34 hours, so 8 people deliver 272 (107.94%).
3. Staff needed = 252 ÷ 34 = 7.4, rounded up to 8.

**Result:** Eight staff on five 8-hour shifts cover 108% of the 252 staff-hours needed, so the roster works with a 20-hour buffer.

## What the result means

Coverage above 100% in total does not guarantee every hour is covered; check the rota so shifts line up with opening hours and peaks.

## Assumptions and limits
- Demand is flat: the same minimum staffing for every open hour.
- Shrinkage is spread evenly across the roster.
- Peaks, skills mix, breaks within shifts and legal rest rules need a detailed rota or workforce-management tool.

## Questions

### What is shrinkage?

The share of paid, rostered time when people are not available to work: leave, sickness, training and meetings. Use your own history.

### Why round staff up?

Because 7.4 people cannot be hired; 7 would leave hours uncovered. The fraction can also be covered with part-time staff or overtime.

## Related calculators
- [FTE Headcount Calculator](https://calculators.geekmidst.com/calculators/fte-headcount-calculator)
- [Team Utilization Calculator](https://calculators.geekmidst.com/calculators/team-utilization-calculator)
- [Part-Time Equivalent Calculator](https://calculators.geekmidst.com/calculators/part-time-equivalent-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/workforce-scheduling-coverage-calculator