Call Center Scheduling Calculator

Erlang C is the industry-standard queuing formula used to calculate how many agents are needed to answer a given call volume within a target service level and answer time. It accounts for random call arrival patterns, so staffing is neither over- nor under-provisioned.

You need your daily call volume, average handle time, target service level (e.g. 80% of calls answered in 20 seconds), and shift/break structure. This calculator runs those inputs through the Erlang C model and factors in break shrinkage to output a required headcount.

Most call centers target 80% of calls answered within 20 seconds, often written as '80/20'. Higher-touch or premium support lines may target 90% or more, while lower-priority queues can accept 70-75% and still remain healthy.

Average handle time (AHT) is the average length of a call plus any after-call work. Longer AHT increases the total workload (in Erlangs) for the same call volume, which directly increases the number of agents required to hit your service level target.

Agents on paid breaks or lunch are not available to take calls, even though they are on the clock. This calculator adds a shrinkage factor based on your selected break lengths so the recommended headcount still covers demand while agents are on break.

This tool gives you a fast, accurate starting point for headcount and shift planning. To actually deploy the schedule, track shift swaps, clock-ins, and time off, a platform like Pebb lets you turn these numbers into live shift plans your agents can see and use in one app.