A vacant role removes capacity only for the hours and work it would otherwise have supplied. Estimate the missing schedule over the vacancy dates, convert it to productive hours if needed, and subtract any confirmed replacement coverage. Keep this operational estimate separate from salary-budget calculations.
Define the vacancy window
Record the last covered date, the first uncovered date and the expected return of coverage. Use the actual working calendar inside that window. A six-calendar-week vacancy does not always mean 240 scheduled hours if it includes closures, part-time days or a role with an irregular schedule.
For a simple illustration, assume six complete 40-hour weeks with no closures. Scheduled hours lost are 6 × 40 = 240. If the role normally contributes 75% of scheduled time to the modeled work, the productive-hours impact is 180.
Add temporary cover in compatible units
Suppose another team provides ten scheduled hours per week for the same six weeks, with the same 75% productive availability. That cover contributes 60 scheduled hours and 45 productive hours. The remaining productive gap is 180 − 45 = 135 hours.
| Item | Scheduled hours | Productive hours at 75% |
|---|---|---|
| Vacant role baseline | 240 | 180 |
| Temporary cover | 60 | 45 |
| Remaining gap | 180 | 135 |
Do not subtract 60 scheduled cover hours directly from 180 productive vacancy hours. That mixes units. If the temporary staff have a different availability or skill mix, calculate their contribution separately instead of copying the vacant role's percentage.
Check where displaced work goes
If existing employees absorb the work, identify what they stop doing or what additional hours they actually provide. Moving work from one team to another does not automatically create organization-wide capacity. A local gap can disappear from one report while becoming a backlog elsewhere.
Track the affected tasks, deadlines and required skills. A role with a unique approval authority may create a bottleneck disproportionate to its total hours. The weekly capacity equivalent cannot show that constraint by itself.
Include the replacement's start-up period
A new hire's first day may end the vacancy in the headcount report without immediately restoring full productive capacity. Model onboarding separately. Account for both the new hire's expected contribution and any mentor time diverted from existing work.
Update the estimate when recruitment dates or temporary coverage change. Label confirmed cover separately from proposed cover. Do not treat an unapproved overtime plan or an unfilled temporary assignment as already available.
Frequently asked questions
Are vacancy savings equal to the lost capacity's value?
No. Salary budget, replacement spending, workload and service outcomes are different measures. This calculation only estimates hours of capacity under explicit assumptions.
Should I report the vacancy as one FTE?
You can report the vacant position's FTE baseline, but include dates and hours as well. One vacant 0.5-FTE role for two weeks is not the same operational gap as a full-time vacancy for a quarter.
Related calculators and guides
- FTE & Headcount Calculator
- Monthly & Annual Work Hours Calculator
- Calculate a Staffing Capacity Gap Before Adding Headcount
Explore more in Workforce Planning Calculators and Guides.