Erlang Calculator

Call Centre Staffing Calculator can calculate up to 10,000 agents! - Now also with Abandons and Day Planner Calculations

Call Centre Erlang Calculator

Calculate the number of staff required to reach an agreed service level

Incoming contacts

in a period of

                                                                                   24 Hours                                          12 Hours                                          10 Hours                                          9 Hours                                          8 Hours                                          1 Hour                                          30 Minutes                                          15 Minutes                                      

Average Handling Time (AHT)

seconds

Required Service Level

% Answered in

Target Answer Time

seconds

Show Advanced Options

        

Statistics from All Erlang Calculations

Number of Erlang Calculations performed
Past 24 Hours	Past Month	Since Feb 2020
6,126	77,816	379,644

Average Values Entered
AHT (Seconds)	370
AHT (Minutes)	06:10
Average Service Level	81.5%
Average Target Answer Time (Seconds)	35.1
Average Shrinkage	27%
Average Max Occupancy	83.7%
Above figures include calls and other work tasks

Average Handling Time (AHT) mm:ss	Percent
0:00 - 0:59	1.4
1:00 - 1:59	3
2:00 - 2:59	6.4
3:00 - 3:59	11.8
4:00 - 4:59	11.2
5:00 - 5:59	13.6
6:00 - 7:59	17.9
8:00 - 9:59	12.2
10:00 - 14:99	9.7
15:00 - 19:99	9.1
20:00+	3.7

How To Use This Erlang Calculator

1. If you have 200 calls per hour, then enter the number of incoming contacts as 200 and the period is 60 minutes.
2. The Average Handling Time is the amount of time that a person (an agent) takes to handle a phone contact. This includes the talk time as well any paperwork time (wrap-up time) before they are able to answer the next call. This should be in seconds.
3. Put in your Service Level target and time. So if you wanted to handle 90% of calls in 15 seconds, put in 90 and 15. If you are uncertain of this the industry "average" is 80% of calls answered in 20 seconds.
4. This contact centre staffing Erlang calculator is a hybrid model based on both the Erlang C formula the Erlang A formula. The Erlang C formula was invented by the Danish Mathematician A.K. Erlang and is used to calculate the number of advisors and the service level. Call Abandons are calculated using the Erlang A formula which was devised by Swedish statistician Conny Palm in 1946. This assumes an Average Patience - also know as Average Time to Abandon (ATA).
5. We also have a more flexible Microsoft Excel based version of this calculator. You can download the free Excel Erlang Calculator
6. This calculator works on probabilities, so may appear to overstate the number of agents needed at low levels. So for example if you enter 0 calls per hour it will say that you need 1 agent. This is quite correct, as there may be a possibility that one call may come in. In practicality, you may decide to not schedule any staff.
7. The maxium number of agents that the calculator can calculate before shrinkage is applied is 10,000 Agents.
8. Shrinkage is a factor designed to take into account holidays, sickness etc. For more information Read this article on how to calculate shrinkage
9. The maximum occupancy is designed to improve accuracy. If you take Occupancy over 85% - 90% for long periods you will find that it gets hidden in a longer AHT figure, and agent burn out happens.
10. Call Abandons are calculated using the Erlang A formula, which assumes an Average Patience -also know as Average Time to Abandon (ATA).