Understanding Balloon Mortgage Amortization
A balloon mortgage is a type of short-term loan that is structured like a traditional long-term mortgage (e.g., 30 years), but requires the remaining balance to be paid in full at a much earlier date (e.g., 5, 7, or 10 years). This final lump sum is the "balloon."
Calculation Methodology
The monthly payment is calculated using the standard annuity formula based on the full amortization term:
$$M = P \frac{r(1+r)^n}{(1+r)^n - 1}$$
- P = Loan amount
- r = Monthly interest rate (Annual rate / 12)
- n = Total number of months (Amortization term × 12)
Numerical Example
If you borrow $200,000 at 6% interest for a 30-year amortization with a 5-year balloon:
- Monthly payment is calculated for 30 years (~$1,199).
- For 60 months (5 years), you pay this amount.
- At month 60, the remaining balance (approx. $184,000) becomes due immediately.