{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"balloon-loan"},"result":{"entity_type":"calculator","id":"balloon-loan","calculator_id":"balloon-loan","canonical_url":"https://tttkmbb.com/finance/balloon-loan","name":"Balloon Loan Calculator","title":"Balloon Loan Calculator – Monthly Payment, Balloon Payment and Total Interest of a Partially Amortized Loan","category":"finance","category_name":"Finance","tool_name":"calculate_balloon_loan","featured_mcp_tool":false,"description":"Computes the payments of a balloon loan: the monthly payment amortized over the full amortization period, the lump-sum balance (balloon) due when the loan matures early, and the total paid and interest up to and including the balloon.","use_when":"You need the monthly payment and final lump sum of a mortgage, commercial or auto loan whose payments are based on a long amortization but which must be repaid or refinanced after a shorter term.","do_not_use_when":"The loan is fully amortized over its term (use loan-payment or amortization-schedule), or payments are interest-only before the lump sum (use interest-only-loan). Informational; not financial advice.","inputs":[{"name":"loan_amount","label":"Loan amount","type":"number","required":true,"max":1000000000000,"exclusive_min":0,"description":"Principal borrowed.","example":200000},{"name":"interest_rate_percent","label":"Annual interest rate","type":"number","unit":"%","required":true,"min":0,"max":100,"description":"Fixed nominal annual rate in percent; the monthly rate is this / 12.","example":6},{"name":"amortization_years","label":"Amortization period","type":"number","unit":"years","required":false,"default":30,"max":100,"exclusive_min":0,"description":"Period over which the monthly payment is calculated as if the loan were fully amortizing (e.g. 30).","example":30},{"name":"balloon_after_years","label":"Balloon due after","type":"number","unit":"years","required":true,"max":100,"exclusive_min":0,"description":"Years until the remaining balance is due as a lump sum; must be shorter than amortization_years.","example":7}],"outputs":[{"name":"monthly_payment","label":"Monthly payment","type":"number","decimals":2,"description":"Level payment that would amortize the loan over amortization_years."},{"name":"payments_before_balloon","label":"Payments before balloon","type":"integer","decimals":0,"description":"Number of monthly payments made before the balloon, 12 × balloon_after_years."},{"name":"balloon_payment","label":"Balloon payment","type":"number","decimals":2,"description":"Remaining balance due with the last scheduled payment (closed-form remaining balance)."},{"name":"principal_paid_before_balloon","label":"Principal repaid before balloon","type":"number","decimals":2,"description":"loan_amount − balloon_payment."},{"name":"total_paid_before_balloon","label":"Total of monthly payments","type":"number","decimals":2,"description":"monthly_payment × payments_before_balloon (excluding the balloon)."},{"name":"total_interest","label":"Total interest","type":"number","decimals":2,"description":"total_paid_before_balloon + balloon_payment − loan_amount."},{"name":"total_cost","label":"Total cost","type":"number","decimals":2,"description":"total_paid_before_balloon + balloon_payment: everything paid over the life of the loan."},{"name":"balloon_share_of_loan_percent","label":"Balloon as share of loan","type":"number","unit":"%","decimals":2,"description":"balloon_payment / loan_amount × 100."}],"input_schema":{"type":"object","properties":{"loan_amount":{"description":"Principal borrowed.","type":"number","maximum":1000000000000,"exclusiveMinimum":0,"examples":[200000]},"interest_rate_percent":{"description":"Fixed nominal annual rate in percent; the monthly rate is this / 12. Unit: %.","type":"number","minimum":0,"maximum":100,"examples":[6],"x-unit":"%"},"amortization_years":{"description":"Period over which the monthly payment is calculated as if the loan were fully amortizing (e.g. 30). Unit: years.","type":"number","maximum":100,"exclusiveMinimum":0,"default":30,"examples":[30],"x-unit":"years"},"balloon_after_years":{"description":"Years until the remaining balance is due as a lump sum; must be shorter than amortization_years. Unit: years.","type":"number","maximum":100,"exclusiveMinimum":0,"examples":[7],"x-unit":"years"}},"additionalProperties":false,"required":["loan_amount","interest_rate_percent","balloon_after_years"]},"output_schema":{"type":"object","properties":{"monthly_payment":{"description":"Level payment that would amortize the loan over amortization_years.","type":"number"},"payments_before_balloon":{"description":"Number of monthly payments made before the balloon, 12 × balloon_after_years.","type":"integer"},"balloon_payment":{"description":"Remaining balance due with the last scheduled payment (closed-form remaining balance).","type":"number"},"principal_paid_before_balloon":{"description":"loan_amount − balloon_payment.","type":"number"},"total_paid_before_balloon":{"description":"monthly_payment × payments_before_balloon (excluding the balloon).","type":"number"},"total_interest":{"description":"total_paid_before_balloon + balloon_payment − loan_amount.","type":"number"},"total_cost":{"description":"total_paid_before_balloon + balloon_payment: everything paid over the life of the loan.","type":"number"},"balloon_share_of_loan_percent":{"description":"balloon_payment / loan_amount × 100. Unit: %.","type":"number","x-unit":"%"}}},"formula":"i = interest_rate_percent / 1200; N = 12 × amortization_years; n = 12 × balloon_after_years; monthly_payment M = P × i / (1 − (1 + i)^−N); balloon_payment = P(1 + i)^n − M((1 + i)^n − 1)/i; total_paid_before_balloon = M × n; total_interest = M × n + balloon − P; total_cost = M × n + balloon","method":"Standard monthly amortization with end-of-month payments; the balloon equals the amortized balance after n payments and is assumed paid with the n-th payment. With a zero rate the payment is P / N and the balloon P − M × n. Lenders round payments to cents, so real balances can differ by a few cents.","sources":[{"name":"CFPB – What is a balloon payment? When is one allowed?","url":"https://www.consumerfinance.gov/ask-cfpb/what-is-a-balloon-payment-when-is-one-allowed-en-104/","type":"government","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Balloon payment mortgage","url":"https://en.wikipedia.org/wiki/Balloon_payment_mortgage","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Amortization calculator (annuity payment formula)","url":"https://en.wikipedia.org/wiki/Amortization_calculator","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"200,000 at 6 %, 30-year amortization, balloon after 7 years","inputs":{"loan_amount":200000,"interest_rate_percent":6,"amortization_years":30,"balloon_after_years":7},"expected":{"monthly_payment":1199.1,"payments_before_balloon":84,"balloon_payment":179278.77,"principal_paid_before_balloon":20721.23,"total_paid_before_balloon":100724.49,"total_interest":80003.26,"total_cost":280003.26},"url":"https://tttkmbb.com/api/v1/calculate/balloon-loan?loan_amount=200000&interest_rate_percent=6&amortization_years=30&balloon_after_years=7"},{"name":"500,000 at 7 %, 25-year amortization, balloon after 5 years","inputs":{"loan_amount":500000,"interest_rate_percent":7,"amortization_years":25,"balloon_after_years":5},"expected":{"monthly_payment":3533.9,"payments_before_balloon":60,"balloon_payment":455810.76,"total_paid_before_balloon":212033.76,"total_interest":167844.52,"total_cost":667844.52},"url":"https://tttkmbb.com/api/v1/calculate/balloon-loan?loan_amount=500000&interest_rate_percent=7&amortization_years=25&balloon_after_years=5"}],"faq":[{"q":"Why is the balloon still so large after 7 years?","a":"Early payments of a 30-year amortization are mostly interest: on 200,000 at 6 % only 20,721 of the 100,724 paid in the first 84 months is principal, leaving 179,279 due."},{"q":"Is the balloon included in total_interest?","a":"No. The balloon is repayment of principal; total_interest = all monthly payments + balloon − loan_amount, which is the interest actually charged over the 7 years."},{"q":"What happens at the balloon date?","a":"The borrower must pay the balance in cash, refinance it or sell the asset; if refinancing is unavailable the loan defaults, which is why CFPB rules restrict balloon features in qualified mortgages."}],"tags":["balloon loan","balloon payment","balloon mortgage","partially amortized loan","remaining balance","commercial loan"],"related":[{"calculator_id":"amortization-schedule","reason":"Full year-by-year balance of the amortization."},{"calculator_id":"loan-payment","reason":"Fully amortizing payment over any term."},{"calculator_id":"interest-only-loan","reason":"Alternative structure with interest-only payments before amortization."}],"links":{"html":"https://tttkmbb.com/finance/balloon-loan","markdown":"https://tttkmbb.com/finance/balloon-loan.md","json":"https://tttkmbb.com/finance/balloon-loan.json","api":"https://tttkmbb.com/api/v1/calculate/balloon-loan","schema":"https://tttkmbb.com/api/v1/calculators/balloon-loan","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:46:20Z","next_actions":[{"tool":"run_calculator","calculator_id":"balloon-loan","reason":"Run Balloon Loan Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/finance/balloon-loan.md"}}