Subdividing a unit into two average costs?

[Dominic Jacquot]

Hello, 

Im planning on purchasing a duplex with 2 large units and subdivide those 2 units into 4 to turn the duplex into a fourplex. Right now im only trying to do the math on this idea but I have no idea of what to expect in terms of costs for the subdivision of those 2 units, does anyone have an Idea of the average cost to expect?

Thank you for your help.