In short
The number of live chat agents you need is set by your busiest hour, not your average day. Multiply chats per hour by handling time, divide by how many chats an agent holds at once, then add spare capacity so most chats are answered within your target. This calculator does that with the Erlang C formula.
Work out your team size
You need about
3 agents
on chat at the same time, or 4 to schedule once breaks and meetings are counted.
- Work arriving
- 1.5 agents' worth
- Answered in time
- 82%
- Agents busy
- 50% of the time
- Chance a chat waits at all
- 24%
How the estimate works
First the calculator turns your traffic into workload: chats per hour multiplied by the time each takes, divided by the number of chats an agent holds at once. Ten chats an hour at six minutes each, handled one at a time, is one agent's worth of work. That is the minimum, with no spare capacity at all.
Then it adds agents until the Erlang C formula says your target is met: for example, 80% of chats answered within 30 seconds. The more agents you add beyond the workload, the shorter the queue gets, with diminishing returns. Finally it adds the time your team is away from chat, such as breaks, training and meetings, to give the number of people to schedule.
Ways to need fewer agents
- Answer repeat questions automatically. An AI assistant that answers from your own content takes the questions with one right answer and hands the rest to people.
- Save the answers you type every day. Saved replies and macros cut handling time, which cuts the workload directly.
- Write the article instead of the answer. Every question you answer in your knowledge base is a chat that never starts. See how to reduce support tickets.
- Set hours you can keep. Honest office hours and an away message stop visitors expecting an instant reply at 3 a.m.
Limits of any staffing formula
Erlang C assumes chats arrive randomly, customers wait patiently and every agent is equally fast. Real traffic is lumpier, some visitors leave, and new agents are slower. Use the result as a starting point, compare it with your real first-reply times in reports, and adjust. Also try the support software cost calculator and the free support templates.
Frequently asked questions
How many live chat agents do I need?
It depends on how many chats arrive in your busiest hour, how long each takes, how many one agent can hold at once, and how fast you want to reply. As a rough guide, 30 chats an hour at 6 minutes each, handled two at a time, needs about 3 agents on chat at the busiest time. The calculator above works out your own number.
What is the Erlang C formula?
Erlang C is the standard queueing formula that contact centres use to work out how many agents are needed so that a chosen share of customers is answered within a chosen time. It takes the workload, the number of agents and the target wait, and returns the chance a customer waits and the share answered in time.
How many chats can one agent handle at once?
Most chat teams run two or three at a time. One at a time is calmer but needs more people; more than three usually slows replies and hurts quality. Start with two, watch your first-reply time and customer ratings, and raise it only if both stay healthy.
What is a good service level for live chat?
A common starting point is answering 80% of chats within 30 seconds, written 80/30. Choose a target your team can keep, and measure it against your office hours. If you cannot meet it, add capacity or let an AI assistant take the repeat questions so people handle the rest.
Why is the number higher than I expected?
Chats arrive in bursts, so you need spare capacity for the busy moments. The calculator also adds time lost to breaks, training and meetings, which is why the number to schedule is larger than the number on chat at once. Reduce the number by answering the repeat questions with saved replies or an assistant.