erlang
Erlang is a unit for measuring how busy a phone line, call centre or service point is, used to decide how many staff or lines you actually need.
In plain English
Remember standing at the bank in Ikeja on a Friday before salary alert, watching only two counters open while the queue snaked past the ATM gallery and out the door? Somebody always says, 'Ah, why do they not open more counters, do they not see this crowd?' That question, the one about how much work is really flowing through a point of service at any given time, is exactly what Erlang was built to answer.
Erlang is a unit of measurement, named after a Danish engineer called Agner Krarup Erlang who worked out how to calculate call traffic on old telephone exchanges. One Erlang simply means one line or one agent being used continuously for one hour. So if you have three customer calls each lasting twenty minutes happening back to back within an hour on one line, that line is carrying one Erlang of traffic.
Businesses use Erlang to plan staffing and capacity properly instead of guessing. A telecom company in Lagos studying how many call centre agents to put on duty between 9am and 12pm, when everybody is calling to complain about data not loading, will use Erlang calculations to know the exact number of agents needed so customers are not left waiting forty minutes for a resolution.
In the United Kingdom, a delivery company handling calls from customers whose parcels have not arrived might use Erlang models to decide staffing for Black Friday week, when call volume triples overnight. Get the number wrong and you either pay staff to sit idle or leave hundreds of customers holding the line while your reputation calmly takes a beating.
For a small business owner in Aba running a customer service line for an online shop, thinking in Erlang terms simply means asking, 'At what hours are people actually calling me, and how many of me do I need at those hours?' You do not need the mathematics, just the mindset. It is capacity planning wearing a technical name.
A customer service line receives calls that add up to 4.5 hours of talk time within a single hour, spread across many callers. That is 4.5 Erlangs of traffic, meaning the business needs roughly five agents on duty at that hour just to keep hold times reasonable, not two.
Questions people ask
Is Erlang only used for phone call centres?
It started there, but the same thinking applies to any place where demand arrives at random times and needs a limited number of servers, tellers or agents, such as bank counters, hospital reception desks or online chat support.
Do I need software to calculate Erlang for my business?
For serious workforce planning, yes, most call centre and scheduling software has an Erlang calculator built in. For a small business, you can start simply by tracking your busiest hours on a notebook and staffing around that pattern.
How is Erlang different from just counting the number of calls?
Counting calls tells you how many people called, but Erlang tells you how much total time those calls actually occupied, which is what really determines how many staff or lines you need.
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