What Is the Erlang C Formula? Related Articles Erlang C Formula - Made Simple With an Easy Worked Example A Beginner’s Guide to the Erlang A Formula Erlang Calculation - An Introduction Excel Based Erlang Calculator for Contact Centres – with Maximum Occupancy © Vitaly - Adobe Stock - 215441621 2,718 Filed under - Definitions, Erlang Calculations The Erlang C formula is a mathematical equation for calculating the number of agents (advisors) that you need in a call centre, given the number of calls and the service level that you want to achieve. Erlang Formula Inputs The inputs to the Erlang C formula are Incoming Contacts (calls) Reporting Period (minutes Average Handling Time (AHT) (seconds) Required Service Level Percentage Target Answer Time (seconds) For example you have 400 calls per half hour. The average time taken to handle a call is 600 seconds and you want to answer 80% of the calls in 20 seconds. There are also a number of ways to extend the basic formula Shrinkage – A factor to include holidays, meetings, training etc Maximum Occupancy (usually set to 85% Average time to abandon (used in the Erlang A formula) Erlang Formula Outputs The main output of the Erlang C formula is the number of agents needed to handle the contact volume. Erlang C Formula Step By Step The mathematics behind it can be quite complex but there is a good article that describes the Erlang C formula step-by-step. The Erlang Calculator Luckily the easiest way to use the Erlang C formula is to use an erlang calculator. There are two main types of Erlang Calculator Online Erlang Calculator Excel Spreadsheet Erlang Calculator Author: Robyn Coppell Published On: 12th May 2022 Read more about - Definitions, Erlang Calculations Recommended Articles Erlang C Formula - Made Simple With an Easy Worked Example A Beginner’s Guide to the Erlang A Formula Erlang Calculation - An Introduction Excel Based Erlang Calculator for Contact Centres – with Maximum Occupancy Contact Centre Reports, Surveys and White Papers Get the latest exciting call centre reports, specialist whitepapers and interesting case-studies. Choose the content that you want to receive. Contact Centre Reports, Surveys and White Papers Invites to exclusive Webinars & Events Weekly Newsletter