I know how do use the pmt() function to calculate mortgage payments but
I need to know the easiest way to calculate the total principle
reduction/remaining balance after a set number of payments without doing
an amortization table.

For example: I finance $500,000 for 30 years at an anual interest rate
of 6% making monthly payments. After 3 years (36 payments) I sell the
asset for $650,000 and want to pay off the remaining principle balance
of the loan. How do I calculate that amount in a one cell formula?
Thanks for the help!!!