THE RIGHT CAPACITY FOR YOUR SERVICE GOAL
Turn contact demand
into a staffing plan.
Estimate the agents needed to meet your service-level target, then explore the full-time equivalent coverage requirement.
Single pooled voice queue · Erlang C · No abandonment
TEST YOUR ASSUMPTIONS
What changes the requirement?
Each scenario changes one assumption. Values show scheduled agents after shrinkage.
Method, assumptions & scope
The calculator finds the smallest whole number of available agents that meets both the service-level target and maximum occupancy. It then divides that requirement by (1 − shrinkage) to estimate scheduled agents.
Offered load = Calls × AHT ÷ Interval seconds
Service level = 1 − Erlang C × exp[−(Agents − Load) × Answer target ÷ AHT]
Weekly FTE = Net agents × Weekly operating hours ÷ [Paid hours per FTE × (1 − Shrinkage)]
Service level = 1 − Erlang C × exp[−(Agents − Load) × Answer target ÷ AHT]
Weekly FTE = Net agents × Weekly operating hours ÷ [Paid hours per FTE × (1 − Shrinkage)]
Erlang C assumes Poisson arrivals, exponentially distributed handling times, a single interchangeable agent pool, an unlimited queue and no abandonment. Calls are handled one at a time. It is a steady-state estimate, not a simulation of changing demand.
Use an interval forecast and scheduling model for a full staffing plan. This preview does not model abandonment, multi-skill routing, chat concurrency, minimum overnight coverage, shift constraints or forecast uncertainty. Zero calls produces zero workload staffing; any minimum coverage must be planned separately.
Weekly FTE is an illustrative flat-demand scenario, not a hiring recommendation. Round-up to whole full-time positions is separate from headcount, which depends on contracts and shift patterns.
Method reference: Gans, Koole & Whitt — Telephone Call Centers: a Tutorial and Literature Review.