{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"refinance-break-even"},"result":{"entity_type":"calculator","id":"refinance-break-even","calculator_id":"refinance-break-even","canonical_url":"https://tttkmbb.com/finance/refinance-break-even","name":"Refinance Break-Even Calculator","title":"Mortgage Refinance Break-Even Calculator – Monthly Savings, Months to Recoup Closing Costs and Lifetime Interest","category":"finance","category_name":"Finance","tool_name":"calculate_refinance_break_even","featured_mcp_tool":false,"description":"Compares the payment on the remaining term of a current loan with a new loan at a different rate and term, and reports the monthly saving, the months needed for savings to recoup closing costs, and the difference in total interest over the life of both loans.","use_when":"You are deciding whether refinancing a mortgage or other amortizing loan is worth its closing costs, given how long you expect to keep the loan.","do_not_use_when":"You want a cash-out refinance amount or an adjustable-rate comparison (this assumes fixed rates), or you only need a payment (use loan-payment).","inputs":[{"name":"current_balance","label":"Current loan balance","type":"number","required":true,"max":1000000000000,"exclusive_min":0,"description":"Principal still owed on the existing loan.","example":200000},{"name":"current_rate_percent","label":"Current interest rate","type":"number","unit":"%","required":true,"min":0,"max":100,"description":"Annual rate of the existing loan in percent.","example":7},{"name":"remaining_term_months","label":"Remaining term","type":"integer","unit":"months","required":true,"min":1,"max":480,"description":"Months left on the existing loan.","example":300},{"name":"new_rate_percent","label":"New interest rate","type":"number","unit":"%","required":true,"min":0,"max":100,"description":"Annual rate offered on the new loan in percent.","example":6},{"name":"new_term_months","label":"New term","type":"integer","unit":"months","required":true,"min":1,"max":480,"description":"Term of the new loan in months (360 for a new 30-year loan).","example":360},{"name":"closing_costs","label":"Closing costs","type":"number","required":false,"default":0,"min":0,"max":1000000000,"description":"Total fees to refinance (origination, appraisal, title, recording).","example":4000},{"name":"finance_closing_costs","label":"Roll closing costs into the new loan","type":"boolean","required":false,"default":false,"description":"If true the closing costs are added to the new principal instead of being paid up front.","example":false}],"outputs":[{"name":"current_monthly_payment","label":"Current payment","type":"number","decimals":2,"description":"Payment that amortizes current_balance over remaining_term_months at current_rate_percent."},{"name":"new_loan_amount","label":"New loan amount","type":"number","decimals":2,"description":"current_balance, plus closing_costs when financed."},{"name":"new_monthly_payment","label":"New payment","type":"number","decimals":2,"description":"Payment on the new loan."},{"name":"monthly_savings","label":"Monthly savings","type":"number","decimals":2,"description":"current_monthly_payment − new_monthly_payment (negative when the new payment is higher)."},{"name":"break_even_months","label":"Break-even","type":"number","unit":"months","decimals":1,"description":"closing_costs / monthly_savings: months of savings needed to recoup the costs (absent when there are no monthly savings)."},{"name":"break_even_time","label":"Break-even time","type":"string","decimals":4,"description":"Break-even in years and months (rounded up to whole months)."},{"name":"remaining_interest_current_loan","label":"Interest left on current loan","type":"number","decimals":2,"description":"current_monthly_payment × remaining_term_months − current_balance."},{"name":"total_interest_new_loan","label":"Total interest on new loan","type":"number","decimals":2,"description":"new_monthly_payment × new_term_months − new_loan_amount."},{"name":"lifetime_savings","label":"Lifetime savings","type":"number","decimals":2,"description":"remaining_interest_current_loan − total_interest_new_loan − closing_costs: net gain over the full life of both loans (negative = refinancing costs more overall)."},{"name":"summary","label":"Summary","type":"string","decimals":4,"description":"Plain-language interpretation of the break-even and lifetime figures."}],"input_schema":{"type":"object","properties":{"current_balance":{"description":"Principal still owed on the existing loan.","type":"number","maximum":1000000000000,"exclusiveMinimum":0,"examples":[200000]},"current_rate_percent":{"description":"Annual rate of the existing loan in percent. Unit: %.","type":"number","minimum":0,"maximum":100,"examples":[7],"x-unit":"%"},"remaining_term_months":{"description":"Months left on the existing loan. Unit: months.","type":"integer","minimum":1,"maximum":480,"examples":[300],"x-unit":"months"},"new_rate_percent":{"description":"Annual rate offered on the new loan in percent. Unit: %.","type":"number","minimum":0,"maximum":100,"examples":[6],"x-unit":"%"},"new_term_months":{"description":"Term of the new loan in months (360 for a new 30-year loan). Unit: months.","type":"integer","minimum":1,"maximum":480,"examples":[360],"x-unit":"months"},"closing_costs":{"description":"Total fees to refinance (origination, appraisal, title, recording).","type":"number","minimum":0,"maximum":1000000000,"default":0,"examples":[4000]},"finance_closing_costs":{"description":"If true the closing costs are added to the new principal instead of being paid up front.","type":"boolean","default":false,"examples":[false]}},"additionalProperties":false,"required":["current_balance","current_rate_percent","remaining_term_months","new_rate_percent","new_term_months"]},"output_schema":{"type":"object","properties":{"current_monthly_payment":{"description":"Payment that amortizes current_balance over remaining_term_months at current_rate_percent.","type":"number"},"new_loan_amount":{"description":"current_balance, plus closing_costs when financed.","type":"number"},"new_monthly_payment":{"description":"Payment on the new loan.","type":"number"},"monthly_savings":{"description":"current_monthly_payment − new_monthly_payment (negative when the new payment is higher).","type":"number"},"break_even_months":{"description":"closing_costs / monthly_savings: months of savings needed to recoup the costs (absent when there are no monthly savings). Unit: months.","type":"number","x-unit":"months"},"break_even_time":{"description":"Break-even in years and months (rounded up to whole months).","type":"string"},"remaining_interest_current_loan":{"description":"current_monthly_payment × remaining_term_months − current_balance.","type":"number"},"total_interest_new_loan":{"description":"new_monthly_payment × new_term_months − new_loan_amount.","type":"number"},"lifetime_savings":{"description":"remaining_interest_current_loan − total_interest_new_loan − closing_costs: net gain over the full life of both loans (negative = refinancing costs more overall).","type":"number"},"summary":{"description":"Plain-language interpretation of the break-even and lifetime figures.","type":"string"}}},"formula":"payment(P, r, n) = P × r/1200 / (1 − (1 + r/1200)^−n). current_payment = payment(current_balance, current_rate, remaining_term); new_amount = current_balance (+ closing_costs if financed); new_payment = payment(new_amount, new_rate, new_term); monthly_savings = current_payment − new_payment; break_even_months = closing_costs / monthly_savings; lifetime_savings = (current_payment × remaining_term − current_balance) − (new_payment × new_term − new_amount) − closing_costs","method":"Assumes both loans are fixed-rate and held to maturity, ignores the time value of the savings and any tax effects. A new loan with a longer term can lower the payment yet raise lifetime interest; both figures are reported so the trade-off is visible.","sources":[{"name":"CFPB – Owning a Home: refinancing","url":"https://www.consumerfinance.gov/owning-a-home/","type":"government","retrieved_at":"2026-09-24"},{"name":"Investopedia – Refinance: What It Is, How It Works, Types and Example","url":"https://www.investopedia.com/terms/r/refinance.asp","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 7 % with 25 years left → 6 % for 30 years, 4,000 costs","inputs":{"current_balance":200000,"current_rate_percent":7,"remaining_term_months":300,"new_rate_percent":6,"new_term_months":360,"closing_costs":4000},"expected":{"current_monthly_payment":1413.56,"new_loan_amount":200000,"new_monthly_payment":1199.1,"monthly_savings":214.46,"break_even_months":18.7,"break_even_time":"1 year 7 months","remaining_interest_current_loan":224067.52,"total_interest_new_loan":231676.38,"lifetime_savings":-11608.86},"url":"https://tttkmbb.com/api/v1/calculate/refinance-break-even?current_balance=200000&current_rate_percent=7&remaining_term_months=300&new_rate_percent=6&new_term_months=360&closing_costs=4000"},{"name":"300,000 at 6.5 % with 28 years left → 5.5 % for 28 years, 6,000 costs financed","inputs":{"current_balance":300000,"current_rate_percent":6.5,"remaining_term_months":336,"new_rate_percent":5.5,"new_term_months":336,"closing_costs":6000,"finance_closing_costs":true},"expected":{"current_monthly_payment":1941.05,"new_loan_amount":306000,"new_monthly_payment":1786.94,"monthly_savings":154.11,"break_even_months":38.9,"remaining_interest_current_loan":352192.21,"total_interest_new_loan":294410.3,"lifetime_savings":51781.91},"url":"https://tttkmbb.com/api/v1/calculate/refinance-break-even?current_balance=300000&current_rate_percent=6.5&remaining_term_months=336&new_rate_percent=5.5&new_term_months=336&closing_costs=6000&finance_closing_costs=true"}],"faq":[{"q":"Why can monthly savings be positive while lifetime savings are negative?","a":"Because resetting a loan to a new 30-year term spreads the balance over more months: the payment falls, but interest accrues for longer. Compare with a new term equal to the remaining term to isolate the rate effect."},{"q":"What break-even period is acceptable?","a":"A common rule of thumb is to refinance when you expect to keep the loan well beyond the break-even point, e.g. a 19-month break-even is attractive if you will stay at least 3–5 years."}],"tags":["refinance calculator","refinance break-even","mortgage refinance","closing costs","rate and term refinance","monthly savings"],"related":[{"calculator_id":"mortgage-payment","reason":"Full payment of the new mortgage with taxes and insurance."},{"calculator_id":"amortization-schedule","reason":"Year-by-year balance of either loan."},{"calculator_id":"loan-payment","reason":"Payment for any balance, rate and term."}],"links":{"html":"https://tttkmbb.com/finance/refinance-break-even","markdown":"https://tttkmbb.com/finance/refinance-break-even.md","json":"https://tttkmbb.com/finance/refinance-break-even.json","api":"https://tttkmbb.com/api/v1/calculate/refinance-break-even","schema":"https://tttkmbb.com/api/v1/calculators/refinance-break-even","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:47:06Z","next_actions":[{"tool":"run_calculator","calculator_id":"refinance-break-even","reason":"Run Refinance Break-Even Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/finance/refinance-break-even.md"}}