Partially Amortized Loan Calculator for Balloon Loans

A partially amortized loan, often called a balloon loan, is repaid with regular installments that do not fully retire the principal by the due date. The remaining balance comes due as a lump-sum balloon payment. Borrowers use this structure when they expect to refinance, sell the asset, or make a large payment later, and want lower installments than a fully amortizing loan of the same term would require. The partially amortized loan calculator sizes the monthly payment so that the unpaid principal equals the balloon at the end of the term. It first discounts the balloon back to present value at the monthly interest rate, subtracts that amount from the loan, and amortizes the difference over the scheduled months. At a zero interest rate the payment is simply the non-balloon principal divided by the number of months. Total payments equal the installments plus the balloon, and total interest is that sum minus the original loan amount. Balloon loans carry refinancing and liquidity risk. If rates rise, credit tightens, or the asset cannot be sold, the borrower may be unable to pay or refinance the balloon. Lenders may also charge fees, require reserves, or reset the rate before maturity. The estimate assumes a constant rate, end-of-month payments, and no extra principal, taxes, insurance, or fees. Actual statements can differ because of day-count conventions, payment timing, and rounding. Use the calculator to compare a balloon structure with a fully amortizing alternative, to see how a larger balloon lowers the installment, and to estimate total interest if the loan runs to term. Enter the balloon as a dollar amount no greater than the loan. The result is a planning estimate, not a lender quote, payoff figure, or advice to take balloon debt. Confirm the note, amortization schedule, and refinance plan with the lender before relying on any payment.