{"name":"loan-amortization-calculator","description":"Calculates a loan's amortization and shows how extra payments shorten payoff and cut interest. Computes scheduled monthly payment, payoff months, total interest, total paid, and interest saved from extra monthly payments. Use it as a loan amortization calculator API, debt payoff schedule, or extra payment interest savings calculator.","price":"$0.01","method":"POST","input_schema":{"properties":{"principal":{"type":"number","description":"Initial loan principal."},"annual_rate":{"type":"number","description":"Annual interest rate as percent."},"term_months":{"type":"number","description":"Loan term in months."},"term_years":{"type":"number","description":"Alternative loan term in years when term_months is omitted."},"extra_monthly_payment":{"type":"number","description":"Optional extra monthly principal payment. Default 0."}},"required":["principal","annual_rate"]},"input_example":{"principal":420000,"annual_rate":6.8,"term_years":30,"extra_monthly_payment":250},"output_example":{"calculator":"loan-amortization-calculator","score":74.2,"grade":"strong","recommendation":"Proceed with standard diligence and covenant checks.","metrics":{"total_monthly_payment":2988.51,"payoff_months":300,"total_interest":476553.25},"drivers":[{"name":"debt_service_coverage","score":83.6,"weight":0.3,"note":"1.42x DSCR"}],"warnings":[],"source":"deterministic in-process finance calculator; no upstream API"},"x402_payment_required":true,"x402_facilitator":"https://api.cdp.coinbase.com/platform/v2/x402"}