A balloon mortgage differs from a regular mortgage primarily in its repayment structure. With a traditional mortgage, you make regular payments of both principal and interest over a set term, typically 15 or 30 years, by the end of which the loan is fully paid off.
In contrast, a balloon mortgage has lower regular payments that cover only the interest and a small part of the principal for a shorter term. Then, you can expect the full amount to be due at the end of the term.