New Version of Excel Based Erlang Calculator for Contact Centres

Call Centre Helper has launched a new version of its popular Erlang C Calculator to help with contact centre staffing calculations.

The new version is built using Python instead of VBA, after Microsoft tightened its security around VBA macros making macro-enabled spreadsheets harder to use.

The updated spreadsheet is available to download here.

Free Updated Version of Erlang Calculator in Excel Format
Version:	1
Date Added:	26 March 2026
File Type:	xlsx
File Size:	18.3 KB
Download Link:	Download

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How Do I Know If I Can Use Python?

To check whether Python is available in your version of Excel:

1. Open Excel.
2. Select the Formulas tab in the top menu.
3. Look for an option called Insert Python with a blue icon.

If you can see this option, Python is available in your version of Excel.

Please note that you must also be signed into your Office 365 account. If you are not signed in, Excel may display #BLOCKED when you try to run Python code. This is because Python calculations run on Microsoft’s servers rather than on your local computer.

What Is Different?

With Python, the spreadsheet has been simplified and now works more like a straightforward form.

One of the key advantages is that the calculator can handle significantly larger volumes of calls than the online version of the tool.

For example, during testing we successfully calculated staffing requirements for:

• 86,395 calls in 30 minutes
• Average Handling Time: 257 seconds
• Service Level: 80%
• Maximum Occupancy: 85%
• Shrinkage: 30%

This resulted in a requirement of 20,731.5 agents, which the spreadsheet was able to process successfully. The online tool would not normally handle calculations of this size.

Of course, if the values entered become extremely large, the mathematical calculations may eventually exceed the limits of the platform.

Running Calculations

While a calculation is running, you may notice a green outlined circle with a theta (θ) symbol next to the answer cells.

You may also see #BUSY displayed. This simply means that the calculation is in progress.

Please wait until the calculation finishes before changing any inputs.

Because Python calculations run on Microsoft’s cloud platform rather than on your computer, the speed may vary depending on your Office 365 subscription and Microsoft’s available compute capacity.

In some cases, Microsoft may temporarily reduce the processing power available if many calculations have been performed. This does not stop the spreadsheet from working, but it may make calculations slightly slower. Microsoft currently resets these limits periodically.

Understanding Erlang

If you would like to learn more about Erlang and how it works in contact centre planning, read this article

Useful Background Articles

If you need help calculating some of the inputs used in the spreadsheet, these articles may help:

• How to Calculate Average Handling Time (AHT)
• How to Calculate Occupancy in the Contact Centre
• What is Call Centre Shrinkage and How to Calculate It?

Known Issues

If the numbers entered are too large for the Erlang C calculation to process, you may see #PYTHON! displayed in the answer cells.

When this happens, the requested calculation exceeds the limits of the platform and cannot be processed within the spreadsheet.

You can find a list of common Python-related errors here.

Feedback

If you would like to share feedback or suggest improvements, please use our feedback form.

As this tool is provided free of charge, any further updates may take time to implement and some requests may not be implemented if they are unlikely to benefit the wider community.

Python in Excel is also a relatively new feature, and future changes will depend on developments from Microsoft.

Author: Jo Robinson
Reviewed by: Robyn Coppell