Balloon Mortgage Calculator

How a Balloon Mortgage Differs

A balloon mortgage amortises as if over a long period (often 30 years) but actually matures in a much shorter term (5, 7, or 10 years). Monthly payments are low because they follow the 30-year schedule, but a large lump sum, the balloon, is due when the shorter term ends.

Where Balloon Mortgages Appear

Balloon structures are used by borrowers expecting a lump sum (a property sale, maturing investment, or inheritance) timed near the balloon date, and carry real risk if refinancing fails or rates rise before it arrives. In some markets, including the United States, residential use narrowed after 2008; commercial property lending continues to use the structure widely.

Quick example

With a loan amount of 400,000 and an interest rate of 7% (a 30-year amortisation period and the balloon due in year 7), the result is 364,589.66.

Which inputs matter most

Measured at the sample figures, Loan Amount moves Balloon Payment Due most, about 1% per 1%, while Interest Rate moves it 0.11%. Balloon Due In moves it the other way. In the sample figures, 91% of the loan is still owed when the balloon arrives; early payments are mostly interest, so seven years of instalments barely dent the principal. The quiet lever is the amortisation period: sizing payments over 15 years instead of 30 cuts the balloon from about 364,600 to about 263,700, because more of each payment reaches the principal. A percentage point on the rate adds only about 5,300 to the balloon, and the loan amount scales everything proportionally.

Why the balance barely moves

In the early years of a long amortisation schedule, most of each payment is interest: at 7% over 30 years, roughly seven-eighths of the first payment goes to interest, so the balance falls slowly and the balloon stays close to the original loan. The front-loading is also why stretching the balloon date helps less than expected: doubling the years to the balloon from 7 to 14 reduces the balance owed by only about 16%, not half.

What the headline figure hides

The headline figure here is a balance, not a cost. What the structure costs shows up in the secondary rows: total paid including the balloon against the amount borrowed. Fees, insurance, rate resets at refinancing, and any early-repayment charge sit outside the calculation and vary by lender.