Loan Constant

The yearly percentage of interest which remains the same over the life of an amortized loan, based on the monthly payment in relation to the principal originally loaned. For example: A $1000 loan at 9% interest for 20 years can be amortized at $9.00 per month. A constant interest rate is figured by finding one year's payments ($9.00 X 12 months = $108.00), and expressing this amount as a percentage of the principal originally borrowed (10.8% of $1000).