This metrics shows the average length of a chat. Chat duration is calculated as the time between the first message in the chat and the time when the chat ends.
Chats Duration metric represents how long a chat is open. It's different than average Handle time because it's NOT how long the AGENT is on it, but how long in total the chat is open with the customer from when it is first started until it ends.
Formula: Chat Duration = Timestamp of last message - Timestamp of the first message
Example: Agent A started a chat at 10:30 am (Timestamp of the first message) and he/she finished the chat at 11:45 am (Timestamp of the last message). Putting this into the formula we will get 11:45 - 10:30 = 1h15min