Actual Required FTE Calculation

Caption showing FTE - Full Time Equivalent

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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.

Question asked by JVAR01

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:

With thanks to Jonty

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?

With thanks to Jonty

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?

With thanks to noah

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?

With thanks to noah

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.

With thanks to Ivan

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.

With thanks to Bon

How to Calculate Shrinkage

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

How to Calculate Contact Centre Shrinkage

With thanks to Jonty

How to Determine 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

With thanks to adnan

No That is the Wrong Formula

Hi Adnan

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.

With thanks to Jonty

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

With thanks to Chandra

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

What Is an Erlang Calculator?

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

With thanks to Jonty

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.

With thanks to Adity

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.

With thanks to Cris

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 ?

With thanks to Mike

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

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

You will then need to use an Erlang Calculator

With thanks to Jonty

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.

With thanks to meynardo

Pop It Into the Erlang Calculator and Select 12 Hours

This will show the FTE per interval

With thanks to Jonty

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 efficency
  • Annual FTE cost 50,000 USD
  • AHT is 3400 seconds as an last information

With thanks to Andrea

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

With thanks to Jonty

FTE Number of Hours In Call Centre Helper Simulator

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.

With thanks to João

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 ?

With thanks to rahul



What pattern of incoming cases in each hour is needed 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?

With thanks to jimmy

The Formula to Use is the Erlang Formula

Erlang C Formula – Made Simple With an Easy Worked Example

With thanks to Jonty

Author: Jonty Pearce

Published On: 12th Apr 2022 - Last modified: 14th Apr 2022
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