Need a quick rule of thumb to estimate renovation costs

[Kenneth Soles]

So I bought a large 3 story duplex at the county tax sale real cheap. It's in pretty rough shape. I am thinking about gutting it and converting it to four 3 bedroom apartments. I am trying to get a budgetary number of what this may cost. Dimensions are 45 feet by 26 feet. Want to do all new mechanics. Also new vinyl siding. Just trying to see if this is something I should pursue or move onto something else. This is located in southwestern Pennsylvania. Is there a formula to calculate by the square foot how much a renovation typically costs? Any help would be appreciated. Thanks