{
  "slug": "extra-mortgage-payment-vs-invest-difference",
  "title": "Extra Mortgage Payment vs Invest the Difference Calculator",
  "heading": "Extra Mortgage Payment vs Invest Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/extra-mortgage-payment-vs-invest-difference",
  "summary": "See whether extra principal payments or investing the same amount builds more wealth.",
  "description": "This calculator focuses specifically on making extra principal payments on an existing mortgage versus redirecting that same monthly amount into a taxable brokerage account. It models the interest saved and years shaved off the loan from extra payments against the compounded growth of investing instead, using your mortgage rate and expected market return.",
  "formula": "Interest Saved = Reduction in total interest from extra principal, amortized. Invest Value = FV of the same monthly amount at expected return.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=extra-mortgage-payment-vs-invest-difference",
  "inputs": [
    {
      "id": "balance",
      "label": "Current mortgage balance",
      "kind": "number",
      "hint": null,
      "default": 280000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "rate",
      "label": "Mortgage rate",
      "kind": "number",
      "hint": null,
      "default": 6,
      "unit": "%",
      "min": 0,
      "max": 15
    },
    {
      "id": "remainingYears",
      "label": "Years remaining",
      "kind": "number",
      "hint": null,
      "default": 25,
      "unit": null,
      "min": 1,
      "max": 30
    },
    {
      "id": "extraMonthly",
      "label": "Extra monthly amount",
      "kind": "number",
      "hint": null,
      "default": 400,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "investReturn",
      "label": "Expected investment return",
      "kind": "number",
      "hint": null,
      "default": 8,
      "unit": "%",
      "min": 0,
      "max": 20
    }
  ],
  "outputs": [
    {
      "id": "winner",
      "label": "Higher-value path",
      "format": "raw",
      "hint": null,
      "primary": true
    },
    {
      "id": "investValue",
      "label": "Investing path value",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "interestSaved",
      "label": "Mortgage interest saved",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "diff",
      "label": "Difference",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "monthsSaved",
      "label": "Months shaved off mortgage",
      "format": "raw",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Current mortgage balance: 280000 $",
      "Mortgage rate: 6 %",
      "Years remaining: 25",
      "Extra monthly amount: 400 $",
      "Expected investment return: 8 %"
    ],
    "outputs": [
      "Higher-value path: Invest",
      "Investing path value: $380,411",
      "Mortgage interest saved: $95,593",
      "Difference: $284,818",
      "Months shaved off mortgage: 97"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter current mortgage balance ($).",
      "Enter mortgage rate (%).",
      "Enter years remaining.",
      "Enter extra monthly amount ($).",
      "Enter expected investment return (%).",
      "Read your higher-value path 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": 170000,
        "rate": 6,
        "remainingYears": 15,
        "extraMonthly": 250,
        "investReturn": 4.8
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "balance": 280000,
        "rate": 6,
        "remainingYears": 25,
        "extraMonthly": 400,
        "investReturn": 8
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "balance": 450000,
        "rate": 6,
        "remainingYears": 30,
        "extraMonthly": 650,
        "investReturn": 12.8
      }
    }
  ],
  "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 is this different from the general payoff-vs-invest tool?",
      "a": "This one is mortgage-specific and models exact amortization with your extra payment reducing principal each month, showing precisely how many months it shortens the loan by."
    },
    {
      "q": "Which option is more predictable?",
      "a": "Paying extra principal is fully predictable — you know your mortgage rate. Investing depends on market performance, which can vary widely and even be negative over shorter windows."
    },
    {
      "q": "Does prepaying trigger any penalty?",
      "a": "Check your loan terms — most conventional mortgages issued in the last decade don't have prepayment penalties, but some older or non-conforming loans do."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/mortgage-payoff-vs-invest",
    "https://www.revenuelab.fyi/toolbox/refinance-vs-keep-mortgage-cost"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Extra Mortgage Payment vs Invest the Difference Calculator (https://www.revenuelab.fyi/toolbox/extra-mortgage-payment-vs-invest-difference)"
}