{
  "slug": "mortgage-15-vs-30-year",
  "title": "15-Year vs 30-Year Mortgage Calculator",
  "heading": "15-Year vs 30-Year Mortgage Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/mortgage-15-vs-30-year",
  "summary": "See the payment gap, total interest saved, and how much faster you build equity.",
  "description": "The 15-year mortgage carries a lower rate and pays off in half the time but comes with a materially higher monthly payment. The 30-year keeps payments manageable and frees up cash flow that can be invested elsewhere. This tool compares monthly payment, total interest paid over the life of each loan, and the equity gap at any given year so you can weigh cash-flow flexibility against total interest saved.",
  "formula": "Payment = P × r(1+r)^n / ((1+r)^n − 1). Total Interest = (Payment × n) − P. Equity gap compares remaining balance at a chosen year.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=mortgage-15-vs-30-year",
  "inputs": [
    {
      "id": "principal",
      "label": "Loan amount",
      "kind": "number",
      "hint": null,
      "default": 400000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "rate15",
      "label": "15-year rate",
      "kind": "number",
      "hint": null,
      "default": 5.75,
      "unit": "%",
      "min": 0,
      "max": 15
    },
    {
      "id": "rate30",
      "label": "30-year rate",
      "kind": "number",
      "hint": null,
      "default": 6.5,
      "unit": "%",
      "min": 0,
      "max": 15
    }
  ],
  "outputs": [
    {
      "id": "interestSaved",
      "label": "Interest saved with 15-year",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "pay15",
      "label": "15-year monthly payment",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "pay30",
      "label": "30-year monthly payment",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "monthlyGap",
      "label": "Extra monthly cost of 15-year",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Loan amount: 400000 $",
      "15-year rate: 5.75 %",
      "30-year rate: 6.5 %"
    ],
    "outputs": [
      "Interest saved with 15-year: $312,283",
      "15-year monthly payment: $3,322",
      "30-year monthly payment: $2,528",
      "Extra monthly cost of 15-year: $793"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter loan amount ($).",
      "Enter 15-year rate (%).",
      "Enter 30-year rate (%).",
      "Read your interest saved with 15-year 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": {
        "principal": 240000,
        "rate15": 3.4499999999999997,
        "rate30": 3.9
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "principal": 400000,
        "rate15": 5.75,
        "rate30": 6.5
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "principal": 640000,
        "rate15": 9.200000000000001,
        "rate30": 10.4
      }
    }
  ],
  "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": "Is the 15-year always the better deal?",
      "a": "Financially it almost always saves total interest, but only if the higher payment doesn't crowd out retirement saving, emergency funds, or higher-return investing."
    },
    {
      "q": "Can I get the same benefit with a 30-year and extra payments?",
      "a": "Largely yes — pay a 30-year like a 15-year voluntarily and you capture most of the interest savings while keeping the lower required payment as a safety net in a bad month."
    },
    {
      "q": "Why is the 15-year rate usually lower?",
      "a": "Lenders take on less risk over a shorter term, so 15-year rates typically run 0.4-0.75 points below 30-year rates."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/mortgage-payoff-vs-invest",
    "https://www.revenuelab.fyi/toolbox/extra-principal-vs-invest"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — 15-Year vs 30-Year Mortgage Calculator (https://www.revenuelab.fyi/toolbox/mortgage-15-vs-30-year)"
}