{
  "calculator": "mortgage",
  "formulaVersion": "mortgage-1.1.0",
  "verifiedOn": "2026-08-21",
  "scope": "Fixed-rate principal and interest with optional monthly principal prepayment",
  "cases": [
    {
      "inputs": {
        "principal": 350000,
        "annualRatePercent": 6.5,
        "termMonths": 360
      },
      "expected": { "monthlyPayment": 2212.24 }
    },
    {
      "inputs": {
        "principal": 120000,
        "annualRatePercent": 0,
        "termMonths": 120
      },
      "expected": { "monthlyPayment": 1000, "totalInterest": 0 }
    }
  ]
}