{
  "slug": "amortization",
  "title": "Amortization Calculator",
  "heading": "Amortization Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/amortization",
  "summary": "See how much of each payment goes to principal vs. interest.",
  "description": "Break down a fixed-rate loan into total interest paid and balance after a given number of payments.",
  "formula": null,
  "dateModified": "2026-10-03",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=amortization",
  "inputs": [
    {
      "id": "amount",
      "label": "Loan amount",
      "kind": "number",
      "hint": null,
      "default": 250000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "rate",
      "label": "Interest rate",
      "kind": "number",
      "hint": null,
      "default": 6.5,
      "unit": "%",
      "min": 0,
      "max": null
    },
    {
      "id": "years",
      "label": "Loan term",
      "kind": "number",
      "hint": null,
      "default": 30,
      "unit": "years",
      "min": 1,
      "max": 50
    },
    {
      "id": "after",
      "label": "Show balance after (years)",
      "kind": "number",
      "hint": null,
      "default": 5,
      "unit": "years",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "monthly",
      "label": "Monthly payment",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "balanceAfter",
      "label": "Remaining balance",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "interestPaidSoFar",
      "label": "Interest paid so far",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "principalPaidSoFar",
      "label": "Principal paid so far",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Loan amount: 250000 $",
      "Interest rate: 6.5 %",
      "Loan term: 30 years",
      "Show balance after (years): 5 years"
    ],
    "outputs": [
      "Monthly payment: $1,580.17",
      "Remaining balance: $234,027.44",
      "Interest paid so far: $78,837.65",
      "Principal paid so far: $15,972.56"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter loan amount ($).",
      "Enter interest rate (%).",
      "Enter loan term (years).",
      "Enter show balance after (years) (years).",
      "Read your monthly payment 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": {
        "amount": 150000,
        "rate": 6.5,
        "years": 18,
        "after": 3
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "amount": 250000,
        "rate": 6.5,
        "years": 30,
        "after": 5
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "amount": 400000,
        "rate": 6.5,
        "years": 48,
        "after": 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 does the amortization calculator work?",
      "a": "Break down a fixed-rate loan into total interest paid and balance after a given number of payments."
    },
    {
      "q": "What do I need to enter?",
      "a": "4 values: loan amount, interest rate, loan term, and show balance after (years). 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 monthly payment 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/loan",
    "https://www.revenuelab.fyi/toolbox/auto-loan"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Amortization Calculator (https://www.revenuelab.fyi/toolbox/amortization)"
}