Calculate Yield on Mortgage Note

Yield is the amount of the profit divided by the amount of money invested.
Yield is also called “return on investment.”

Mortgage Note Estimator Free Quote

For example, you own a mortgage where original balance was $100,000.
There were originally 120 payments due and your interest rate is 10%.
Your mortgage has 66 monthly payments still outstanding of $1,321.51 each.
You have been offered $50,000 for this mortgage by the note buyer.
What yield is the note buyer intending to get?

Amount offered for  the loan?
Yield to note buyer? (%)
Number of payments left 
Number of payments per yr?
Payment amount (usually monthly) ?