Staffing Calculator for Email Queues

How do you work out the number of staff you need for email queues? Is is possible to use an Erlang Calculator for this?

Sayan asked our Community of industry professionals for advice:

Is Erlang suitable to estimate agents for email queues, where the SLA may be 2 hours? So in the calculator if the SLA is set to 100% in 7200 seconds, would it produce a viable result?

The AHT which we have tracked is ~ 20 mins. So, if the TAT is around 2 hrs (i.e. 100% of the emails to be answered in 2 hrs) and with an AHT of 20 mins, Erlang C will give us the correct figure for agents required?

Please note, we do know the day of week and interval-wise forecast (i.e volume) per 30 mins interval.

What I need is a calculator sort of a thing, where I will put –

• Weekly /day of week volume
• Intraday pattern
• AHT
• Shrinkages & Occupancy
• SL / TAT

and the calculator will tell me the number of agents required to cater to the volume.

Would you recommend another approach?

You Can Use Erlang C to Calculate Email Queues

Erlang C calculates the optimum number of resources required to accomplish a number of tasks across a time interval, so emails would be perfectly OK within these parameters.

The thing to watch out for is the resources and the volume of mails… it’s perfectly OK to say 7200 seconds, but the key number will also be the average amount of time it takes an agent to complete an email.

So you will need to time track the time from when the agent opens up the email, to the time they resolve it and send a response back. If you can’t track that, then you might struggle with doing the correct calculation.

You simply need to replicate the same parameters you use in your inbound phone calls to your inbound emails (number in queue, number of agents, average handling time, number of new emails per interval, etc.)

Erlang C can be applied regardless of the length of time involved. Supermarkets use Erlang C to calculate the number of tills required at certain time of the day as well as civil engineers who design sidewalks or motorways for traffic… so emails will work perfectly well too.

You can use our free online Erlang calculator

You Can Also Use Microsoft Excel

Things like work volume, AHT, etc, are elements that directly calculate the erlang requirements. So, if you’re using MS excel to determine this, I would recommend a crash course on how to produce macros.

From there, you can have separate pages which will have your work levels over an interval, number of staff, AHT, etc… and then run a macro which will run an Erlang C calculation based on all of the variable factors you want to throw at it.

Unfortunately, I wont be able to go over the exact formulas to apply here, but I’m sure there are places on the internet which will help you get there.

With thanks to Gene

How Do I Calculate the Amount of Staff Needed to Manage Return Requests?

I need to calculate how many staff I need for my process. We manage return request for an online seller.

Currently I have 6 people who are logged in to work for 9 hours a day excluding the break of 1 hour.

The average time spent on each return is 7 to 8 mins and out of the 100 returns assigned to each individual they work on at least 60 unique cases a day with multiple emails sent on each unique case.

With thanks to Dave

Avoid Understaffing

People logged in for 9 hours a day with an hour for lunch is too much. They are going to be burnt out and the quality will go down.

If you were based in the UK and doing this for 5 days a week you would probably be breaking labour laws.

By my quick calculations you could probably handle 57 cases a day. If you are allocating 100 then you are seriously understaffed and I would guess that workload is backing up.

With thanks to Simon Bell

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You may also find these articles helpful to read next:

• Erlang Calculators Explained
• How to Calculate Occupancy in the Contact Centre
• How to Calculate FTE Requirements

Author: Jonty Pearce
Reviewed by: Megan Jones