I’m in need of a formula that requires taking the result of a series calculations, and by then modifying the result, tell me what one of the starting values is. In simple terms…2 x 3 = 6, but what if I wanted to change the 6 to a 7 and find out what the number 3 becomes, assuming the 2 was a constant. That would require that the variable number 3 would need to change to 3.5. It’s this sort of challenge I have, but in more complicated terms.

The calculation I’m after takes a value calculated from a given set of inputs, one of which is Price, to arrive at a percentage called Cash-on-Cash. I need to be able to reverse the calculations so that by modifying the Cash-on-Cash I can arrive at a new Price. Some of the inputs will change and some will remain constant. Many of the variables change in relation to each other as most of them are portions of loan costs.

The inputs are:

NOI (Constant)
Annual Debt Service (Variable – This is annual loan payments)
Total Invested (Variable – This is a combination of the next 4 items)
Down Payment (Variable – % of Price)
Points (Variable – % of Price)
Closing Costs (Variable - % of Price)
Other Costs (Constant)
Interest Rate (Constant)
Term (Constant)

Cash-on-Cash (Variable)
Price (Variable)

If anyone can assist me in this I’d be happy to provide the workbook where the forward calculations are present. It’s the revers calculation that I’m struggling with.