Partially amortized loan planner Compare the lower scheduled payment against the large balloon still due at maturity so you can gauge refinance or sale pressure before the term ends.
Assumptions
This page uses a fixed APR with monthly compounding. The regular payment is based on the longer amortization period, while the schedule stops at the shorter balloon term and shows the unpaid balance still due at maturity.
Year inputs are rounded to the nearest month. Fees, escrow, taxes, rate resets, interest-only periods, prepayment penalties, and refinance approval are outside this model.
Display currency
The currency preference changes how values are shown in the result sheet and schedule. It does not change the amortization math.
Result
$2,918.69 / month
Scheduled payment based on a 360-month amortization, with a balloon still outstanding after 120 months.
Balloon payment
$383,854.50
Cash due at maturity
$386,773.19
Principal repaid before balloon
$66,145.50
Interest paid before balloon
$284,097.47
Remaining principal at maturity
85.3%
Interest share of scheduled payments
81.11%
Maturity checkpoint
After payment 120, the remaining balance is still $383,854.50. If the note requires the scheduled payment and balloon payoff on the same date, the maturity cash need is $386,773.19.
The last scheduled payment in the table includes $755.26 of principal and $2,163.43 of interest before the separate balloon payoff.
Amortization chart
Principal vs interest leading to the balloon payment
A partially amortized loan calculator shows the trade-off that makes these loans attractive and risky at the same time: the regular payment is lower because it is spread over a long amortization period, but the note matures earlier and leaves a large balloon still due.
What a partially amortized loan actually means
A partially amortized loan separates the payment schedule from the legal maturity date. The payment is calculated as if the debt will amortize over a longer period, such as 25 or 30 years, but the actual note may come due after only 5, 7, or 10 years. Because the loan does not reach a zero balance by the maturity date, the unpaid balance becomes a balloon payment.
That structure is common in commercial real estate, certain business loans, and some niche mortgage situations where lenders want a shorter reset point than the full amortization period. The lower scheduled payment can improve short-term cash flow, but it also concentrates risk at maturity because the borrower must be able to refinance, sell the asset, or bring cash to pay the remaining balance.
How the calculator works
The calculator converts APR into a monthly rate, converts both the amortization period and the shorter balloon term into months, and then uses the standard fixed-rate amortization payment formula to determine the scheduled monthly payment. It then walks month by month through the shorter term to show how much of each payment goes to interest, how much reduces principal, and what balance remains when the balloon comes due.
The important distinction is that the loan is not recalculated to fully pay off by the balloon date. Instead, the monthly payment follows the longer amortization period, while the balance at the earlier maturity date becomes the balloon payoff. That is why the page reports both the monthly payment and the maturity cash need.
Monthly rate = APR / 12
APR is converted into a monthly nominal rate for the fixed-rate planning model.
Monthly payment = standard amortizing payment over the full amortization term
The scheduled payment is based on the longer amortization period, not the shorter balloon maturity.
Balloon payment = Remaining balance after the shorter loan term
The balloon is the unpaid principal left after the last scheduled payment before maturity.
Worked example: 450,000 at 6.75% with a 30-year amortization and 10-year balloon
Suppose the original balance is 450,000, the APR is 6.75%, the amortization period is 30 years, and the note matures after 10 years. This calculator estimates a scheduled monthly payment of about 2,918.69 because the payment is spread across the full 360-month amortization schedule rather than a full payoff in 120 months.
After 120 scheduled payments, the balance is still about 383,854.50. That means only about 66,145.50 of principal has been repaid before maturity, while about 284,097.47 has gone to interest. If the final scheduled payment and balloon are due together, the maturity cash need is about 386,773.19. That is the planning reality behind common searches such as balloon payment calculator, loan term vs amortization period, and commercial balloon loan calculator.
What this estimate does not cover
This is a fixed-rate monthly planning model. It does not include fees, points, taxes, insurance, escrow, default interest, prepayment penalties, interest-only periods, variable-rate resets, or lender-specific underwriting conditions that can materially change the real refinance or payoff path.
Use the result sheet to understand the size of the refinance problem before maturity, not to replace a lender disclosure. If you are evaluating a commercial or consumer balloon loan, compare the scheduled payment with the likely remaining balance and think through whether the loan still works if rates, collateral value, or refinance availability move against you.
What is the difference between a partially amortized loan and a fully amortized loan?
A fully amortized loan reaches a zero balance at the end of the term because every scheduled payment is sized to pay off the debt completely by maturity. A partially amortized loan uses a longer amortization period than the actual term, so the scheduled payment is lower but a large balance is still outstanding when the note matures.
Why is the balloon payment still so large after years of monthly payments?
Because early payments on a long amortization schedule are heavily interest weighted. When the loan matures early, many of those scheduled payments have covered interest but have not reduced principal by very much. The result is a large remaining balance even after several years of on-time payments.
Can I refinance a partially amortized loan before the balloon date?
Possibly, but the calculator cannot assume that refinance will be available. Lenders may look at current rates, property or collateral value, debt-service coverage, loan-to-value, business performance, and your credit profile when the balloon date approaches. A partially amortized loan should be evaluated with a refinance or sale plan in mind, not with an assumption that refinancing will always be easy.
Do extra principal payments reduce the balloon amount?
Yes. If extra principal is applied without changing the contracted maturity date, the remaining balance at the balloon date falls because more of the debt has already been paid down. This calculator does not model those extra payments, so treat the result as the baseline schedule before any principal curtailment strategy is added.
