Your actual cost per call will vary based on the average amount of time you spend on calls (average talk time), plus the after call work time. Cost will also vary based on call complexity - collections calls require less expensive agents than technical support calls. And, your internal costs for real-estate, technology, etc. impact your cost structure.
There are many numbers floating around the industry for cost per call within the US. A few years ago, Forrester published a cost per call of $33 and Gartner $5.50. I've also seen internal cost studies where the cost per call was less than $3.00. The cost per call is much lower abroad in places like India and the Philippines than in the US.
This was first published in September 2005