FTE Calculation at a monthly

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FTE Calculation at a monthly
How can I use Erlang to find the right number of FTE for a monthly volume? How can consider the fact that the call center is open during 12 hours but the employees work 7 hours. Do I need to adjust the supply par 30 minutes in considering the fact that an employee work 7 hours instead of 12 hours? Does my question is clear? Sorry my first language is french, I do my best in English. Thank you so Munch. Here is the data: 27 355 calls per month, 21 workings days, service level 80, Target answer time 20, AHT 302.3. So to consider the situation, my supply by 30 minutes is:(27 355/21/6.5)*30/60 = 100 Am I right? The number of FTE according to Erlang C and this data is: 21


Call Centre Helper

You need to create a weekly daily and hourly profile
There are approx 4.2 weeks in a month, so approx 6510 calls per week.

But across the week the calls are not distributed evenly. So a typical breakdown
Monday 23.8%
Tuesday 20.8%
Wednesday 19.8%
Thursday 18.8%
Friday 16.8%

So for a Monday you would have 23.8% x 6510 = 1549 calls
If you put this into the Erlang Calculator
1549 calls, 12 hours, 302.3 seconds 80/20 service level gives a peak of 31.5 Agents (21.5 Agents average across the 12 hours).


Thank you for your answer. However, I'm looking for the right number of employees to hire to meet that demand. My answer is 21 and 30 employees with a shrinkage factor of 30%. What do you think about that.

Thank you


Call Centre Helper

To get an accurate number you would have to do your own modelling of demand
21 employees will leave you understaffed.

To get an accurate number you would have to do your own modelling of demand.

Try to find the call arrival patterns, which days, which hours etc and then you can get a more accurate figure.

I'M looking for the hiring plan. For the moment, the objective is not to break down a day by interval. I'm working on the long term plan. Considering 30 ressources so 21 FTE, I will not be understaff. Il will not cover all interval but this is the right number that I need to meet the service level. I don not want to be overstaff. Here is the proof that the demand for the months will be cover with 21 FTE: 21 * 7 hours by day* 11,91 calls per hour(3600/302.3 AHT)*21 business day: 36 766 potential calls to be handling. This potential volume is higher than the demand of 27 355. What's wrong? Thank you so munch


Call Centre Helper

You assume that all calls arrive evenly spaced across the day
Call volume varies across the day. You also need to take account of shrinkage.

Use this tool to help you

Is it possible to do...
Is it possible to download this tool? Thank you

My objective is to find the number of ressources to hire at the beginning of the year. I Know that the call volume varie across the week and day. Once I have found the right ressources to hire, I'll Schedule the ressources to minimize shortfalls. However, I do not want to cover the max interval or to be staff to cover all intervals of monday beacause I'll be overstaff for the rest of the week. I want the mean of ressources needed. Do you understand my position? I think you can use Erlang C at high level (monthly) to find the right number of ressources whithout to check by interval. Scheduling by intervall will be the next step. What do you think about that?


Call Centre Helper

Scheduling by interval is good
There is an excel version of the Erlang calculator but it is not as functional as the online version

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