Find a local contractor, invite and pay for their lunch and ask them to give you their formula to estimate renovations.

The taxpayer and EAT may enter into agreements or arrangements relating to the purchase or sale of the property, including puts and calls at fixed or formula prices, effective for a period not in excess of 185 days from the date the property is acquired by the EAT.g.

I have been wildly successful using my formula above which has yield a large robust portfolio that is cash flowing more than $7000 /mo with little to none of my own money.   

Instead we rented it for a song knowing all the money would be made on the sale not on CF.

The things we MUST have as investors from our lenders:Using rental income immediately to help me qualifyAbsolutely no seasoning requirementsUsing the ARV immediatelyAnd some othersAnd in this formula, even if you are only going to use commercial/portfolio style of loans - you should be getting a 30 year, fixed rate loan.  

When comparing sell or hold options, what formulas are most helpful?

The capitalization rate of an investment can be calculated by dividing the property's net operating income (NOI) by the current market value or acquisition cost of a property - expressed in the following formula: Cap Rate = Net Operating Income / Current Market Value " Chicago Cap Rate Analysis Please keep in mind this is a high level analysis.It should give you a ballpark idea of cap rates in the various Chicago neighborhoods.But some assumptions were made for this analysis.For example, to determine the net income for a property, I assumed it would be 50% of the Gross Rental Income.

So if you buy a 3 unit that has 2 units rented a $1500 apiece and one vacant for you to live in there is a formula the banks use I believe and a good percentage if not all of the $3000 of monthly rental income plus whatever other monthly income you have minus your expenses counts toward the amount you need to qualify for the mortgage.

there is a formula that I can use?

@Johnny McKeonThis reminds me of a line in a Chris Rock song..."