Erlang Calculator
User manual

Version 4.1
Erlang Calculator Logo


CCmath’s Erlang Calculator is a one of a kind Excel add-in for workforce management professionals. You can calculate your metrics in Erlang-C and -X, blending and chat models, all within your own worksheets with our custom functions. The Erlang-X Microsoft Excel add-in is used by many contact centers as a planning assistant, as it provides a full capacity calculation suite for Excel with all functions and parameters needed. Anyway, thanks for downloading and let’s get started!

How to get started

After installing the Erlang Calculator, please open the add-in from the Home ribbon. Once you have logged in with a Microsoft 365 account (please check the minimal requirements which can be found here), you can start the process of getting your free trial week by clicking on the ‘Manage subscription’ button. During this week you can use all functions the add-in provides for free. We advise you to start by reading this manual and trying our three demo sheets. In the paramagraphs below and on our website we explain all functions and assist you during this period. Please visit our FAQ page if you experience trouble.

Please be aware that after your trial ends, your subscription will automatically continue and the fee will be deducted from your account. You can manage your subscription in your personal dashboard. You can access this by clicking ‘Manage Subscription’ on the right side panel in Excel, after selecting the Erlang Calculator in the Home-ribbon. Or by signing in on our website

In your dashboard you can find your invoices, upgrade from Basic to Premium, cancel your subscription and read our policies and terms. In the left column you can see your current subscription, when your subscription started and when your next billing cycle starts.


If you experience trouble with the Erlang Calculator, please visit this page. Here you can find a more in-depth explanation of the demo sheets and find answers to frequently asked questions. For more in-depth questions and troubles please create a ticket in our Support center, or mail us at

Function parameters

The following parameters can be used in the Erlang functions provided by our add-in. We recommend reading all definitions and note the requirements. Please be aware that the time unit of all parameters must be the same when you make your calculations. For an example, see our FAQ page.

Parameters Definition and requirements


Depending on their values, either the Erlang C, Erlang X, or a combination of the two models is used in the following functions. Note that some parameters in the Erlang X functions are optional, these parameters are cursive and grey. If an optional parameter is used, all other optional parameters must also be filled in.
Function Parameters Result of calculation
In the blending model, agents will work on inbound as well as outbound calls. If an agent becomes available, they will prioritize inbound calls and will only take on outbound calls when Threshold other agents are left idle.
Function Parameters Result of calculation
In the model for chats, the distinguishing feature is that agents can handle multiple chats in parallel.
Function Parameters Result of calculation