Erlang C calculator
Work out how many people you need on a shift to handle your contact volume within the target time, with the method contact centers use.
Results are estimates based on the numbers you enter. They vary with your operation.
How Erlang C works
Load in Erlangs is how many people you would need if contacts arrived evenly: contacts × handle time ÷ period length.
Erlang C gives the probability that a contact waits with N people, and from it the share answered within the target. The calculator finds the smallest N that meets your service level without exceeding the maximum occupancy.
Finally it adds shrinkage: if 30% of paid time is not spent on contacts, you need to schedule more people than those handling contacts at once.
Load (Erlangs) = contacts × handle time ÷ period length
Frequently asked questions
What does an 80/20 service level mean?
80% of contacts answered within 20 seconds. It is the most common goal for phone support; chat usually allows a longer time.
Does Erlang C work for chat?
As a reference, yes, but in chat one person can handle several conversations at once, so you usually need fewer people than the calculation shows.
How do I reduce the number of people I need?
By reducing the contacts that reach your team. An AI agent that resolves repetitive requests lowers the load in Erlangs and, with it, the staff you need.
Let an AI agent answer for you
ChatNorris answers on your website, WhatsApp, Instagram and more channels, trained on your content. When it needs to, it hands off to your team with a summary.