Balloon mortgages generally have lower interest rates. A balloon payment is a large payment due at the end of a mortgage.Balloon mortgages usually have terms ranging between five and seven years and lower interest rates than traditional fixed-rate mortgages. This tool figures a loan's monthly and balloon payments, based on the amount borrowed, the loan term and the annual interest rate. A balloon loan is usually rather short, with a term of three to five years, but the payment is based on a term of up to 15 years. Balloon Mortgages typically offer lower interest rates and payments, but they may be too risky for some homebuyers. Call Scott D. Rogoff at . A balloon mortgage has an interest rate that is fixed for an initial amount of time. At the end of the term, the remaining principal balance is due.