Actual Required FTE Calculation

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Required FTE for inbound call volumes
I wanted to get feedback on how actual required FTE is being calculated by others for inbound call volumes.

I'm including occupancy in Forecasted FTE required, to account for a call centre environment in which its not realistic that an agent can handle calls back to back.

When calculating actual FTE required, historically the model has utilised actual occupancy in the calculation of FTE required. However I believe this inaccurately inflates the requirement.

However not accounting for occupancy in the requirement generates a misleading FTE number since the business would never run at 100% occupancy.


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How many staff you need

How to Work out How Many Staff You Need in a Contact Centre

This article gives you a step by step look at How many Staff you need in your contact centre.
It goes through all of the steps needed to staff your contact centre.

The Erlang Calculator - for contact centre staffing

Another useful tool is the Call Centre Helper Erlang Calculator:


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Look at Forecast Accuracy

If it is a forecast then it will be wrong.
That is the nature of forecasting.

You need to start tracking your forecast accuracy to see what your forecast accuracy is. Read this article about calculating forecast accuracy:

You can then model it to see if there is a better value. A lot depends on averages. If you use an average occupancy figure for the year, then you may well find monthly variances, as more people take holiday during the summer and more people get ill during the winter.

Are you using Erlang calculations to work out the number of FTE required?



How do You Calculate FTE?

  • How do you convert workload time into hours and into seconds?

  • How do you calculate workload into the amount of FTEs needed?

  • How do you calculate FTEs?



Check this calculation
I have 2 questions:

1. If 100 calls arrive in 30 minutes, and each call takes on average three minutes to service, then each agent can take ten calls per hour.

Is this correct, it doesn\\\'t make sense to me when I do the math.

100(calls)*180(AHT)/3600 (hour). I get 5, not 10 calls per hours.

Can someone clarify the above for me?

2. Same question for grossing up for planned absence/vacancy?

So basically,

1000 calls * 600 AHT/ 80% / 3600 = 208.33 hours

with shrinkage of 15% (x 1.15) = 239.58 hours

with absents of 10% (x 1.10) = 263.54 hours

I just want to also know if the above hours also mean the same thing as FTE requirements.
So for example 263.54 hours is approximately 263.5 FTE is that correct?

WFM Analyst

Correct workings for FTE
Hi Noah

First answer: 100(calls)*180(aht)/3600 (hour) I get 5, not 10 calls per hours.

The result should be giving 5 FTE needed. But you are saying "100 calls arrive in 30 minutes",then you should divide 1800 instead of 3600 then you will get answer of 10 FTE required.

Second Answer: 263.54 was hours not FTE. If 1 FTE production hour was 8 then you will need 263.5 / 8 hours = 32.9 FTE

I assume you have used 80% occupancy in your formula.

Hi everyone, how com...
Hi everyone, how come we are multiplying shrinkage here? It should be base staff/hours divide by (1-shrink), right? Thanks.


Call Centre Helper

How to Calculate Shrinkage
This article walks through all the steps on how to calculate shrinkage. It should help

how to detemine how many FTE i need
I need some help calculating FTE needed for an activity
Volume per month = 177,
Handle Time = 174 seconds
1 agent works 160 hours per week
28% of that time is shrinkage - therefore productive time is 115.2.
the formula I have used to determine FTE is ((Volume per month*handle time/60)/60)/(115*0.9)
The FTE number I get is 0.08, this does not seem right to me
is this correct formula to use?
any help would be appreciated


Call Centre Helper

No that is the wrong formula
You need to break the monthly volume down into days (it is not evenly spread across the month) and use an Erlang Calculator.

I also think that you mean 1 agent works 160 hours per MONTH (40 hours per week).

The answer will probably work out as between 1 and 2 FTE.

FTE required for above question
volume per month = 177
Handle time = 174 sec = 2.9 minutes

1 agent works for 160 hour per month. (5days *8hours*4 weeks)
Shrinkage = 28% = 160 of 28% = 115.2 hours is the productive hours

FTE required = ( 177*2.9)/115.2 = 4.45 FTE

FTE required = ( 177*2.9)/60/115.2 = 0.04 FTE.
As the AHT is in minutes, we need to convert it in to hours


Call Centre Helper

This is the wrong calculation
Chandra - You have assumed that all tasks are evenly distributed across the day. This is not the case and will leave you understaffed.

You need to factor in your desired service level and use an Erlang Calculator
More details in these articles

Follow-Up question
I used the Erlang's formula to get daily requirement of manpower (hourly split included).
I need to understand if I have to run 2 shifts - one 8 Hr shift for 21 days and other 12 Hr shift for 15 days, how many people should i hire?
Basically, i need to extrapolate one-day requirement to a monthly requirement, considering the shifts to be arrange in a fashion where the resources get periodic offs and fit into the 2 shift structures mentioned above.
Any help would be appreciated.

FTE for live chat
Hello, How can we compute FTE for live chat agents who are able to handle multiple customers with different chat durations at the same time?

Any help is greatly appreciated.

adding the Service level
I am trying to determinate my required FTE,
I have my monthly required hours 2500, shrinkage 18%, agents 8 hours on 23 days
so =(2500/8/23)-((2500/8/23)*18%)= 11 FTE
If I want to add the service level at 80% what should I do more please ?


Call Centre Helper

That would leave you seriously understaffed
This assumes that the work is evenly distributed across the period, which it will not be. That would leave you seriously understaffed

First read this article

You will then need to use an Erlang Calculator

any help will do
If you required 15 FTE but the call centre is only open 12 hours.
How many seats do I need to prepare.


Call Centre Helper

Pop it into the Erlang Calculator and select 12 hours

Need help for annual FTE calculation
The problem is how much FTE needed if you want to increase active selling ratio to %30 in 1 year. I will try to calculate is it feasible to make an IT investment (250,000 USD one time and regularly 5,000 USD) or not? What is the feasible amount to decide open a web sale channel or not?

  • 1,000,000 calls

  • %10 active selling

  • 252 days

  • 8 hours with %50 effiency

  • Annual FTE cost 50,000 USD

  • AHT is 3400 seconds as an last information


Call Centre Helper

You need to break it down into days and hours
You need to break it down into days and hours and then put it into an Erlang Calculator

FTE Number of hours in CallCentreHelper simulater
In your tools that you offer online and for download, how many working hours do you consider an FTE.

Is is possible to adjust if required. I suppose in some places a working day is 8hr, in others 8.5. Others might be less.

FTE calculation
out of 40 hours, I am saving 30 mins everyday due to a recent process improvement implementation. how much FTE I am saving ?


Table below showes pattern of incoming cases in each hour in different queues.
We know that shrinkage is 40%, please calculate how many FTE is needed in each hour to handle incoming volume. All FTE's workload is 1(8hours)

AHT is 10 sec and cases 1000 let's say.
What is the right formula?


Call Centre Helper

The formula to use is the Erlang Formula

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