tell me your strategy in determining sellers equity

[Jose Falconett]

How do you determine the equity in a property using public records after getting off the phone with the seller if they don't have the payoff statements to prove to you.

Public records only show principal and length of mortgage (15-30)yrs typically. The interest I would assume based on historical averages. 

I don't know how to account for taxes, PMI, homeowners insurance, and refinances, when plugging into a mortgage amortization calculator. http://www.mortgagecalculator.org/calculators/mort...

If I give you a scenario can you show me your strategy for equity?         $80k mortgage note recorded January 2005 

                                                            6% interest rate