That's way more accurate than trying to back-in using a formula. 

Income property is all about the numbers and having one obscure number (or formula) off in one of your spreadsheets could throw your projections way off and cause you to lose the confidence of your investors.

There is almost zero vacancy right now in our area - of course, it would be some time to get things ready and build and have ur first renters.Are there some math formulas that help?

I have been on the BP calculator, but when I get to certain questionable items, I have no idea what to enter without getting false estimate.Is there a formula I can use?

One of the best things I learned I feel for simplicity and profit sake is the purchase formula. 70 percent of ARV less repairs is max you should offer for buy fix and flip I have seen it mentioned here and heard it a while back on one of San Antonio's premier investors podcast I have bought and sold about 10 houses a year the last 3 years I went back and worked numbers on closed sales after the fact and when I was in the 70 percent range or less and minus repairs on my purchase price I did great.

@Russell GronskyIRR and NPV both use the same underlying formula to arrive at a result, they just solve for different things.

If so, would I use a different formula other than the 'ARV' for coming up with an asking price for this particular type of property?

In my opinion, for any income-generating asset, you're best bet for determining value will be to use the cap rate formula:Cap Rate = NOI / ValueWhere NOI is "Net Operating Income" and Cap Rate is the ROI based on an all-cash (no debt service) purchase.If you switch the formula around, you get:Value = NOI / Cap RateWhile NOI and Cap Rate are going to be specific to the property and the location, if you want a really rough estimate for typical properties and typical real estate markets, you can assume:- NOI equals gross income divided by two- Cap Rate equals 10%So, let's say that your triplex generates about $800 per unit per month.

Rich Dad Poor DadRich Dads Cash Flow QuadrantRich Dads Increase your financial IQThe Real Book of Real EstateThe ABC’s of RE InvestingThe ABC’s of PMRich Dad RE Tax AdvantagesThe E-MythThe 4 Hour Work Weekhttp://flip2freedomacademy.com - free e-bookFlip2freedom episode 77[http://www.flip2freedom.com/a-3-step-formula-to-a-successful-balanced-and-insanely-profitable-2012/] - podcast - LISTEN TO THIS TODAY!

Steve, do you have a formula that you use to help determine the repair expenses?