@Andrew McCotterAgree with Joe but I’ll state it in terms of ROE because I look at number *and* percentages ;-)Take the formula for ROE:Return on Equity = Net Cash Flow/Total Equity InvestedFinancing will reduce your net cash flow by the amount of debt service which decreases ROE.

I have about the same doors and find Excel easy to keep up my my properties during the year and for tax season.I fill out the same sections each year and based on the formulas I have it place it gives me all the final numbers I need for each property all in one place.

The risk/return formula seems to work better for the mixed offerings (given a great management team of course). 

There is no magic formula - just take action and do one step at a time. 

Is there a formula for that?

Is there a formula or method to find the ARV when analyzing triplex or fourplex properties.

Or is there a more complicated formula that needs to be followed to merge both the original building basis with the value of the improvements?

Once you move into a triplex or four Plex they use some sort of formula based on the rents and the property that can make it difficult to qualify most multi units under FHA guidelines.  

My formula requires we use tremendous discipline and research, looking at some 100+ deals for each one we close. 8) Unable to Move to Other Markets - I have bought in eight different markets.

I've yet to find the magic formula, but not for lack of trying.