{
  "id": "student-loan-payoff",
  "version": "2c01e68cf75a",
  "status": "published",
  "name": "Student Loan Payoff Calculator",
  "question": "When is my student loan payoff?",
  "summary": "Computes how many months a student loan takes to pay off at the current payment plus extra monthly payments or a lump sum, and the interest and time the extra saves.",
  "category": "finance",
  "subcategory": "loans",
  "url": "https://www.acalculator.org/finance/student-loan-payoff-calculator",
  "markdown": "https://www.acalculator.org/finance/student-loan-payoff-calculator.md",
  "kind": "schedule",
  "method": "Each month, interest = balance × rate ÷ 365.25 × (365.25 ÷ 12) = balance × rate ÷ 12; the payment (current + extra) pays the interest first, then the balance; the last payment is what is left.",
  "assumptions": [
    "Interest is simple daily interest, balance × rate ÷ 365.25 a day, as federal student loan servicers charge, over months of equal length (365.25 ÷ 12 days).",
    "Each payment goes to the interest that built up first, then to the principal. No unpaid interest is capitalized.",
    "The lump sum is paid today, before the first monthly payment; the first payment is one month later.",
    "The rate stays fixed. Several loans can be entered as one balance at their weighted average rate.",
    "Income-driven plans, forgiveness, autopay discounts and fees are not included."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "balance": {
        "title": "Loan balance",
        "description": "What you owe today: principal plus any unpaid interest.",
        "type": "number",
        "x-unit": "USD",
        "exclusiveMinimum": 0,
        "maximum": 10000000
      },
      "rate": {
        "title": "Interest rate",
        "description": "The loan’s yearly interest rate (a weighted average for several loans).",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 30
      },
      "payment": {
        "title": "Monthly payment now",
        "description": "The monthly payment you make now.",
        "type": "number",
        "x-unit": "USD",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "extra": {
        "title": "Extra each month (optional)",
        "description": "An extra amount added to every payment.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000
      },
      "lump": {
        "title": "One-time payment now (optional)",
        "description": "A lump sum paid today, before the first monthly payment.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 10000000
      },
      "start": {
        "title": "First payment month",
        "description": "The month of the next payment. It dates the schedule and the payoff month.",
        "type": "string",
        "format": "date"
      }
    }
  },
  "outputs": {
    "months": {
      "label": "Months to pay it off",
      "description": "The number of monthly payments until the balance is 0, with the extra and the lump sum.",
      "format": "integer"
    },
    "time": {
      "label": "Time to pay it off",
      "description": "The months in years and months.",
      "format": "duration"
    },
    "payoff": {
      "label": "Last payment",
      "description": "The month of the last payment, when a first month is given.",
      "format": "month-year"
    },
    "interest": {
      "label": "Total interest",
      "description": "All the interest paid until the loan is paid off.",
      "format": "money"
    },
    "paid": {
      "label": "Total paid",
      "description": "The balance plus all the interest, lump sum included.",
      "format": "money"
    },
    "baseMonths": {
      "label": "Months at the current payment",
      "description": "Months to pay off with the current payment alone, when it ever pays off within 50 years.",
      "format": "integer"
    },
    "sooner": {
      "label": "Months saved",
      "description": "How many fewer payments the extra and the lump sum take.",
      "format": "integer"
    },
    "saved": {
      "label": "Interest saved",
      "description": "The interest the extra and the lump sum save, compared with the current payment alone.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "balance": 30000,
      "rate": 6.5,
      "payment": 340,
      "extra": 100,
      "start": "2026-10-02"
    },
    "outputs": {
      "months": 86,
      "time": {
        "years": 7,
        "months": 2
      },
      "payoff": "2033-11-02",
      "interest": 7545.212392164197,
      "paid": 37545.2123921642,
      "baseMonths": 121,
      "sooner": 35,
      "saved": 3363.8151145047477
    },
    "text": "Paying $340.00 plus $100.00 a month clears $30,000.00 in 7 years, 2 months, saving $3,363.82 of interest."
  },
  "examples": [
    {
      "given": {
        "balance": 30000,
        "rate": 6.5,
        "payment": 340,
        "extra": 100
      },
      "expect": {
        "months": 86,
        "interest": 7545.212392164197,
        "baseMonths": 121,
        "sooner": 35,
        "saved": 3363.8151145047477
      },
      "source": "Federal Student Aid servicer MOHELA, Student Loan Interest: balance × rate ÷ 365.25 a day, payments to interest first (https://mohela.studentaid.gov/DL/resourceCenter/StudentLoanInterest.aspx, retrieved 2026-10-01); hand calculation in content.mdx; Python 3 month-by-month loop",
      "tolerance": 1e-9
    },
    {
      "given": {
        "balance": 10000,
        "rate": 0,
        "payment": 250,
        "lump": 2000,
        "start": "2026-11-01"
      },
      "expect": {
        "months": 32,
        "interest": 0,
        "baseMonths": 40,
        "sooner": 8,
        "saved": 0,
        "payoff": "2029-06-01"
      },
      "source": "Federal Student Aid servicer MOHELA, Student Loan Interest (https://mohela.studentaid.gov/DL/resourceCenter/StudentLoanInterest.aspx); hand calculation in content.mdx: (10,000 − 2,000) ÷ 250 = 32 payments"
    },
    {
      "given": {
        "balance": 25000,
        "rate": 6.8,
        "payment": 287.71
      },
      "expect": {
        "months": 120,
        "interest": 9523.629383783424,
        "baseMonths": 120,
        "sooner": 0
      },
      "source": "Federal Student Aid servicer MOHELA, Student Loan Interest: $25,000 at 6.8% accrues $4.65 a day (https://mohela.studentaid.gov/DL/resourceCenter/StudentLoanInterest.aspx); hand calculation in content.mdx: 25,000 × r ÷ (1 − (1 + r)^−120) = 287.7008, r = 0.068 ÷ 12",
      "tolerance": 1e-9
    }
  ],
  "sources": [
    "MOHELA (a Federal Student Aid servicer), Student Loan Interest: daily interest = balance × rate ÷ 365.25; payments applied to outstanding interest first, retrieved 2026-10-01. https://mohela.studentaid.gov/DL/resourceCenter/StudentLoanInterest.aspx",
    "MOHELA (a Federal Student Aid servicer), How Payments Are Applied (payments above the amount due can be made at any time without penalty), retrieved 2026-10-01. https://mohela.studentaid.gov/dl/resourceCenter/howpaymentsareapplied.aspx",
    "Consumer Financial Protection Bureau, Find advice for your student loans, retrieved 2026-10-01. https://www.consumerfinance.gov/paying-for-college/repay-student-debt/"
  ],
  "related": [
    "student-loan",
    "loan-payoff",
    "debt-payoff",
    "amortization"
  ],
  "changelog": []
}