What is the Erlang Calculator?

An Erlang Calculator is a powerful mathematical tool used extensively in the contact centre and customer service industries to optimize staffing levels, manage call volumes, and ensure efficient resource allocation. Named after the Danish mathematician A.K. Erlang, this calculator plays a vital role in achieving Grade of Service (GOS) targets and enhancing the overall customer experience.


How the Erlang Calculator Works:

The Erlang Calculator relies on advanced mathematical algorithms to determine the number of agents or customer service representatives required to handle incoming calls effectively during specified time intervals. It takes into account several critical factors:


Traffic Intensity

Traffic intensity refers to the rate at which calls arrive at a contact centre during a given period. The calculator uses this data to assess the load on the system.


Service Level Objectives

Organizations define their service level objectives, specifying parameters such as the maximum acceptable wait time for callers or the desired GOS.


Average Call Handling Time

The calculator considers the average time it takes for an agent to handle a call, including conversation time and any post-call work.



Erlangs are a unit of telecommunications traffic measurement. The calculator utilizes Erlang to represent call volume and intensity.


Offered Load

This metric represents the total number of calls offered to the contact centre during a specific period.


Erlang B and Erlang C Models

The calculator employs Erlang B for modelling blocked calls (those that receive a busy signal due to insufficient resources) and Erlang C for modelling queuing systems (those with waiting times).


How It Is Used in Contact Centre and Customer Service Industries:


Optimizing Staffing

Contact centres use the Erlang Calculator to determine the optimal number of agents required to meet service level objectives. By aligning staffing levels with expected call volumes, organizations can minimize overstaffing and understaffing issues.


Call Forecasting

The calculator assists in predicting call volumes during specific time frames, enabling contact centres to adjust their staffing schedules and resources accordingly. This is particularly valuable in addressing seasonal fluctuations.


Reducing Wait Times

By accurately estimating the necessary staffing levels, organizations can reduce caller wait times, improving customer satisfaction and service quality.


Cost Management

Efficient staffing, as determined by the Erlang Calculator, helps organizations manage costs effectively. It minimizes unnecessary labour expenses while ensuring that customer service demands are met.


Service Level Compliance

Contact centres can consistently achieve their service level objectives by leveraging the Erlang Calculator to align resources with call volumes.


Resource Allocation

Beyond staffing, the calculator aids in allocating resources for various tasks, such as managing email inquiries, chat interactions, and other customer service channels.


In summary, the Erlang Calculator is an indispensable tool for contact centres and customer service operations. It empowers organizations to deliver superior service, optimize resource utilization, and maintain service level objectives, ultimately enhancing the customer experience.


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