cash flow calculators websites

[Bryan .]

Does anyone have a good cashflow calculator website? I have found and used the ones below but none of them account for buying a property below market value when trying to predict future value. Please post one if you have a good one.

www.mortgage-investments.com/Mortgage_and_real_estate_Calculators/investment_rental_real_estate_profit_predictor.htm

http://militaryfinance.umuc.edu/calculators/InvestmentProperty.html

http://www.goodmortgage.com/Calc_investment_property.htm

http://kelloggagency.com/?page=cashflow_calc