A balloon payment is a large payment due at the end of a mortgage. Learn everything you need to know about balloon notes in mortgage loans.Find out how they work and how they can affect your finances. This calculator computes the payment amount necessary for a mortgage with a balloon payment, using monthly interest compounding and monthly payments. A balloon payment loan has lower monthly payments for a set period (generally three to 10 years) and one big "balloon" payment when the loan term ends. The most common balloon loan terms are 3 years and 5 years. After the loan term is complete, you will then need to refinance or pay off the remaining balance.