Use the tool below to calculate the number of active agents you would require for your call center operations, or even for just a specific queue, in order to meet or exceed your pre-determined Service Level Agreements (SLA).
Enter the following data in the edit boxes:
- Average call duration
This parameter refers to the typical duration of a call when an agent is connected to the external party via telephone.
- Average wrap-up time
Average time spent by an agent for wrap-up processing of the call. This is typically the time spent in performing post-call administrative routines.
- Number of calls per hour
It is recommended to perform calculations for different time of the day, for example when the load is maximum and minimum. You may also base this on the different operational queues and the associated SLA.
- Average answering delay that you are prepared to tolerate.
This parameter is calculated across all calls, including those that were connected to the agent immediately, without any queue intervention.
Click the button Calculate.
You will get a table of calculated values on the proposed number of agents needed for your call center operations during the specified hour, depending on the percentage of busy agents.
The table also contains other parameters describing the call center performance: average wait time for customers, probability of immediate connection without queuing, average queue length, and service level achievable.
Calculation Model Brief
The Erlang-C traffic model was developed by the Danish scientist A.K. Erlang and designed for estimating call center performance. This is an analytical formula for modeling telephony systems which involve queuing. As such, it can be applied to the design and analysis of inbound call centers which queue calls prior to presenting them to agents. Poisson distribution is used for modeling the random processing of calls.
It is important to note that this model assumes that the queue has an unlimited capacity. In general, this is not an obstacle if there are sufficient lines in the call center. The Erlang-B calculator can be used to estimate the optimum number of phone lines required for your call center.
Please also note that the Erlang-C calculator has been specially designed to not return a number of agents which is lower than a certain minimum regardless of a large value of call answering delay - for regaining control of the queue of incoming calls without impacting the stability and predictability of the entire system!
