How to calculate FTE requirements on a monthly level

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Could someone please help me with the best practice approaches for forecasting FTE requirements for a 12 month period? (on a month-by-month level) My understanding is that Erlang would not be suitable for this.

Currently we use 2 approaches to get FTE estimates:

1.((Bookings forecast*Contact per booking)*AHT)/(Avg hours worked*Agent availability(%)*Agent Occupancy(%))

2. Bookings forecast/ Avg. Bookings per FTE

It would be great if someone could help with what other best practices in the industry are? Also, are there any tools available to help with more accurate forecasting?

We are trying to improve the accuracy of FTE forecasts at our call center, as a way to lower our cost/booking.

Thanks in advance!


Planning & Performance Manager

Thames Water


It's not 100% clear whether you are accounting for Shrinkages in the calculation at all? maybe that's what the availability is thinking about it.

Number 1) looks good on that basis, presuming you've done some intraday level work to understand the expected Occupancy.

Assume your Availability changes by month based on the various fluctuations of external factors and also internal planning?


Yes, agent availability includes shrinkage due to leaves, training, etc. We currently take agent occupancy as a monthly average - not on an intraday level (since we are trying to forecast FTEs for a longer term, and don't use this process for daily scheduling).

Similarly for agent availability, we are using a yearly average figure (assuming that fluctuations even out over a 12 month period).

Would you suggest doing things differently?

Planning & Performance Manager

Thames Water

Hi Sandy,

I would always suggest you model shrinkages monthly, and certainly plan for them like that as well (in fact, that will go right down to intraday). Holiday demand will peak in certain months and your workload will probably do the same but not necessarily in the same months. If you use the average you may find yourself unexpectedly under staffed or over staffed in certain months. Planning for it will allow you to guide decisions around Training etc. as well.

I would always model your occupancy at an intra day level. If you use historical data and assume an average, you are merely planning to achieve what you did in the past. Ideally you model the impact of differing service levels on the occupancy and schedule fit you can achieve. So in the Long Term Plan you look to have the occupancy you would expect to see by targetting the Service Levels you want to achieve and the ability to staff to the profiles you have. You then can use that number at the monthly level.



hi team am very new in this industry and i would love to know what factor do i have to put into consideration when am doing the forecasting of call, and when am calculating number of agents needed to get a certain services Level

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