They've (Fannie) also reduced their risk by factoring in 25% of expenses which doesn't account for taxes and insurance either because when you take 75% of gross rents you're still subtracting it from principal and interest, taxes, insurance, and assessments through the "PITIA."

So you can get the basic info on a property and then add or subtract them from the comp.

Take your gross revenue and from it subtract all your operating expenses (business licence, property tax, insurance, maintenance, utilities, administration, property management, etc).  

.: $100,000 x 70% = $70,000 then subtract any necessary repairs and your wholesale fee (if any).

I then subtract $3,400 for costs during rehab. 

You might need to figure adding or subtracting for size, age, condition, quality of construction, views, etc.

When I calculate Net Profit Margin, I simply subtract ALL of the costs (including closing costs) from the sales price.  

First I take the rent and subtract the HOA fee.

Do you just subtract the commission from the usual 70% ARV minus repair costs minus my profit?

So, from a sale price of $120,000, we will need to subtract the cost of repairs ($5,000), holding/closing costs ($12,000) and desired profit ($25,000).