Inputs
Example data table
Use this sample to understand the inputs and the output scale.
| Field | Example | Notes |
|---|---|---|
| Baseline daily volume | 1,200 | Normal daily workload units. |
| Peak uplift | 55.0% | Expected seasonal increase. |
| Avg handling time | 3.50 | Minutes per workload unit. |
| Operating pattern | 6d / 2 shifts / 8.00h | Defines standard weekly scheduled hours. |
| Utilization | 85.0% | Productive share of scheduled time. |
| Shrinkage total | 19.0% | Absence + attrition + ramp-up loss. |
| Service buffer | 8.0% | Extra staffing for variability. |
| Estimated headcount needed | 12 | People required for peak week. |
| Estimated additional hires | 0 | After accounting for overtime. |
Formula used
1) Forecast volume
ForecastDaily = BaselineDaily × (1 + Uplift% / 100)
ForecastWeekly = ForecastDaily × DaysPerWeek
2) Weekly workload hours
WeeklyWorkHours = (ForecastWeekly × AHT_minutes) / 60
3) Capacity per person and base FTE
StandardWeekHours = HoursPerShift × ShiftsPerDay × DaysPerWeek
ProductiveHoursPerPerson = StandardWeekHours × Utilization%
BaseFTE = WeeklyWorkHours / ProductiveHoursPerPerson
4) Shrinkage, buffer, and headcount
EffectiveFactor = 1 − (Absence% + Attrition% + RampUpLoss%)
FTE_Needed = (BaseFTE / EffectiveFactor) × (1 + Buffer% / 100)
HeadcountNeeded = ceil(FTE_Needed / AvgFTEperPerson)
5) Overtime adjustment (optional)
OvertimeFTE = (CurrentHeadcount × OT_hours × Utilization) / StandardWeekHours
AdditionalHires = ceil(max(0, FTE_Needed − (CurrentFTE + OvertimeFTE)) / AvgFTEperPerson)
These formulas provide a practical estimate. Adapt utilization, shrinkage, and buffer to match your operational reality.
How to use this calculator
- Enter baseline daily volume and expected peak uplift percentage.
- Set handling time per unit and your weekly operating schedule.
- Choose a realistic utilization target for productive time.
- Add shrinkage rates: absence, attrition, and ramp-up loss.
- Set a service buffer to cover variability and service goals.
- Optionally add overtime and cost assumptions for budgeting.
- Click Calculate staffing, then export CSV or PDF.
Notes for HR & People Ops
- Calibrate handling time: Use time studies or historical KPIs.
- Separate peak roles: If roles differ, run scenarios per role and combine.
- Validate shrinkage: Include planned leave, training, and policy constraints.
- Plan earlier: Lead time is often the hidden bottleneck during peak.
Convert peak demand into weekly labor hours
Apply uplift to baseline volume. Example: 1,200 units with 55% uplift becomes 1,860 per day. At 6 operating days, weekly volume is 11,160 units. Convert units to time with AHT: 11,160 × 3.5 minutes = 39,060 minutes, or 651.0 workload hours weekly.
Turn schedules and utilization into productive capacity
Scheduled hours follow your shift pattern. With 1 shift daily, 8 hours per shift, and 6 days, scheduled hours equal 48. Apply utilization to estimate productive time: 48 × 0.85 = 40.8 productive hours. Base staffing is 651.0 / 40.8 = 15.96 FTE.
Apply shrinkage for absence, attrition, and ramp-up
Shrinkage reduces capacity during peak. Combine absenteeism, in-season attrition, and training ramp-up loss. Using 6% + 3% + 10% gives 19% shrinkage, so effective factor is 1 − 0.19 = 0.81. Adjusted staffing becomes 15.96 / 0.81 = 19.70 FTE.
Add service buffer and evaluate overtime coverage
Buffer protects service targets when demand varies. With an 8% buffer, required staffing becomes 19.70 × 1.08 = 21.28 FTE. If average FTE per person is 0.95, that equals ceil(21.28 / 0.95) = 23 people. With 18 people today, you have 17.10 FTE. If each can do 4 overtime hours weekly, overtime adds (18 × 4 × 0.85) / 48 = 1.28 FTE, leaving a gap that rounds to 4 hires.
Cost the plan and back-plan the hire-by date
Budget the season using wage, overtime premium, and season weeks. With 22 planned people (18 current + 4 hires), weekly regular hours are 22 × (48 × 0.95) = 1,003.2. At 3.25 per hour, regular cost is about 3,260. Using 72 overtime hours at a 1.5 multiplier adds about 351, totaling about 3,611 weekly. Over 8 weeks that is about 28,891, plus one-time hiring costs of 800. Enter a peak start date, then subtract onboarding lead weeks for the hire-by target. Review results with operations weekly as assumptions change fast.
FAQs
1) What should I use for baseline daily volume?
Use a stable, non-peak average from recent weeks. Exclude one-off promotions and outages. If volume is volatile, use the median of 4–8 comparable weeks for a conservative baseline.
2) How do I pick average handling time (AHT)?
Start with historical performance or a time study. Include after-call work, picking travel, or quality checks. If AHT varies widely, test both a typical value and a worst-case value.
3) Why does utilization matter?
Utilization converts scheduled hours into productive capacity. It removes breaks, meetings, coaching, and idle time. Setting it unrealistically high can hide needed headcount and increase burnout risk.
4) What belongs in shrinkage?
Include absence, in-season attrition, and the productivity loss from onboarding. Add other recurring non-productive time only once. Avoid double counting by keeping AHT focused on the work itself.
5) Should I cover gaps with overtime instead of hiring?
Overtime is a fast bridge, but it has limits and fatigue effects. Compare the overtime premium to recruiting and training costs. If the gap is sustained, hiring usually protects quality better.
6) How is the hire-by date calculated?
The tool subtracts onboarding lead weeks from your peak start date. If no date is entered, no hire-by date is shown. Adjust lead weeks to match sourcing time, checks, and training schedules.