{
  "slug": "mortgage-payoff",
  "title": "Mortgage Payoff Calculator",
  "heading": "Mortgage Payoff Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/mortgage-payoff",
  "summary": "What an extra payment each month does to your payoff date.",
  "description": "Extra principal payments hit the back end of an amortisation schedule, where almost all of the remaining interest lives. Even a small monthly addition can cut years off a 30-year loan.",
  "formula": "Compares the scheduled amortisation against the same loan with extra principal applied monthly.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=mortgage-payoff",
  "inputs": [
    {
      "id": "balance",
      "label": "Current balance",
      "kind": "number",
      "hint": null,
      "default": 285000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "rate",
      "label": "Interest rate",
      "kind": "number",
      "hint": null,
      "default": 6.25,
      "unit": "%",
      "min": 0.01,
      "max": null
    },
    {
      "id": "yearsLeft",
      "label": "Years remaining",
      "kind": "number",
      "hint": null,
      "default": 27,
      "unit": null,
      "min": 1,
      "max": null
    },
    {
      "id": "extra",
      "label": "Extra monthly principal",
      "kind": "number",
      "hint": null,
      "default": 300,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "interestSaved",
      "label": "Interest saved",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "monthsSaved",
      "label": "Time saved",
      "format": "duration",
      "hint": null,
      "primary": false
    },
    {
      "id": "newPayoff",
      "label": "New payoff time",
      "format": "duration",
      "hint": null,
      "primary": false
    },
    {
      "id": "payment",
      "label": "New monthly payment",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "scheduledInterest",
      "label": "Interest if unchanged",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Current balance: 285000 $",
      "Interest rate: 6.25 %",
      "Years remaining: 27",
      "Extra monthly principal: 300 $"
    ],
    "outputs": [
      "Interest saved: $99,772.40",
      "Time saved: 93",
      "New payoff time: 232",
      "New monthly payment: $2,123.09",
      "Interest if unchanged: $305,682.30"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter current balance ($).",
      "Enter interest rate (%).",
      "Enter years remaining.",
      "Enter extra monthly principal ($).",
      "Read your interest saved on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "balance": 171000,
        "rate": 6.25,
        "yearsLeft": 16,
        "extra": 175
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "balance": 285000,
        "rate": 6.25,
        "yearsLeft": 27,
        "extra": 300
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "balance": 456000,
        "rate": 6.25,
        "yearsLeft": 43,
        "extra": 475
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "How does the mortgage payoff calculator work?",
      "a": "Extra principal payments hit the back end of an amortisation schedule, where almost all of the remaining interest lives. Even a small monthly addition can cut years off a 30-year loan. The underlying maths is: Compares the scheduled amortisation against the same loan with extra principal applied monthly."
    },
    {
      "q": "What do I need to enter?",
      "a": "4 values: current balance, interest rate, years remaining, and extra monthly principal. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the interest saved result mean?",
      "a": "It is returned as a money amount in US dollars and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/mortgage",
    "https://www.revenuelab.fyi/toolbox/amortization",
    "https://www.revenuelab.fyi/toolbox/refinance"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Mortgage Payoff Calculator (https://www.revenuelab.fyi/toolbox/mortgage-payoff)"
}