Go to wherever the deeds are recorded in your area. Look up the original deed of trust which most cases will show you the amount that it secures and the interest rate. Then any financial calculator and put the data in, compute remaining balance and that is it.
Is there a way to find out how much is still owed on a mortgage? Typically, when a lender forecloses on a property, the judgement amount is shown on the document. But in the case of a lien holder, the mortgage amount is not shown. Can this be determined?