{
  "id": "part-d-penalty",
  "version": "02ea60ac77da",
  "status": "published",
  "name": "Part D Penalty Calculator",
  "question": "What is my Part D penalty?",
  "summary": "Works out the Medicare Part D late enrollment penalty: 1% of the national base premium for each month you went without drug coverage, for 2026 or 2027.",
  "category": "finance",
  "subcategory": "retirement",
  "url": "https://www.acalculator.org/finance/part-d-penalty-calculator",
  "markdown": "https://www.acalculator.org/finance/part-d-penalty-calculator.md",
  "kind": "function",
  "method": "Penalty a month = months without coverage × 1% × national base beneficiary premium ($38.99 in 2026, $41.33 in 2027), rounded to the nearest $0.10.",
  "assumptions": [
    "Only full months count, from the end of your initial enrollment period (or the end of your last creditable coverage) to when your Part D coverage starts.",
    "A gap of fewer than 63 days in a row adds no penalty.",
    "People who get Extra Help pay no late enrollment penalty.",
    "Medicare decides the count of months; this page uses the number you enter."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "months": {
        "title": "Months without drug coverage",
        "description": "Full months after your first chance to join Part D with no Part D plan and no other creditable drug coverage (gaps of 63 days or more).",
        "type": "integer",
        "minimum": 0,
        "maximum": 720
      },
      "year": {
        "title": "Year",
        "description": "The penalty is worked out again each year from that year’s base premium.",
        "type": "string",
        "enum": [
          "2026",
          "2027"
        ]
      },
      "plan": {
        "title": "Your plan’s monthly premium",
        "description": "Optional: your drug plan’s premium, to see the total you pay each month.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 10000
      }
    }
  },
  "outputs": {
    "monthly": {
      "label": "Penalty a month",
      "description": "Months × 1% × the national base premium, rounded to the nearest 10 cents.",
      "format": "money"
    },
    "percent": {
      "label": "Penalty percent",
      "description": "One percent for each month without coverage.",
      "format": "percent"
    },
    "base": {
      "label": "National base premium",
      "description": "The national base beneficiary premium for the year, per month.",
      "format": "money"
    },
    "yearly": {
      "label": "Penalty a year",
      "description": "The monthly penalty times 12.",
      "format": "money"
    },
    "total": {
      "label": "Total premium a month",
      "description": "Your plan premium plus the penalty.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "months": 14,
      "year": "2026"
    },
    "outputs": {
      "monthly": 5.5,
      "percent": 14,
      "base": 38.99,
      "yearly": 66
    },
    "text": "With 14 months without drug coverage, your Part D penalty is $5.50 a month in 2026."
  },
  "examples": [
    {
      "given": {
        "months": 14,
        "year": "2026"
      },
      "expect": {
        "percent": 14,
        "base": 38.99,
        "monthly": 5.5,
        "yearly": 66
      },
      "source": "Medicare.gov, Avoid late enrollment penalties (https://www.medicare.gov/basics/costs/medicare-costs/avoid-penalties): $38.99 × 0.14 = $5.46, rounded to the nearest $0.10 = $5.50"
    },
    {
      "given": {
        "months": 25,
        "year": "2026",
        "plan": 45.5
      },
      "expect": {
        "monthly": 9.7,
        "yearly": 116.4,
        "total": 55.2
      },
      "source": "Medicare.gov rule (1% a month of $38.99, nearest $0.10): 38.99 × 0.25 = 9.7475, $9.70; plus a $45.50 plan premium"
    },
    {
      "given": {
        "months": 14,
        "year": "2027"
      },
      "expect": {
        "base": 41.33,
        "monthly": 5.8,
        "yearly": 69.6
      },
      "source": "CMS fact sheet, July 28, 2026 (https://www.cms.gov/newsroom/fact-sheets/medicare-part-d-2027-national-average-monthly-bid-amount-information): 2027 base premium $41.33; 41.33 × 0.14 = 5.7862, $5.80"
    },
    {
      "given": {
        "months": 500,
        "year": "2026"
      },
      "expect": {
        "monthly": 195
      },
      "source": "Half-way case: 38.99 × 5.00 = 194.95, which rounds half up to $195.00 (hand calculation)"
    },
    {
      "given": {
        "months": 0,
        "year": "2026",
        "plan": 12
      },
      "expect": {
        "monthly": 0,
        "total": 12
      },
      "source": "Medicare.gov: no months without creditable coverage means no penalty"
    }
  ],
  "sources": [
    "Medicare.gov, Avoid late enrollment penalties: https://www.medicare.gov/basics/costs/medicare-costs/avoid-penalties (retrieved 2026-10-05)",
    "Centers for Medicare & Medicaid Services, 2026 Medicare Part D Bid Information and Part D Premium Stabilization Demonstration Parameters (July 28, 2025): https://www.cms.gov/newsroom/fact-sheets/2026-medicare-part-d-bid-information-and-part-d-premium-stabilization-demonstration-parameters (retrieved 2026-10-05)",
    "Centers for Medicare & Medicaid Services, Medicare Part D 2027 National Average Monthly Bid Amount Information (July 28, 2026): https://www.cms.gov/newsroom/fact-sheets/medicare-part-d-2027-national-average-monthly-bid-amount-information (retrieved 2026-10-05)"
  ],
  "related": [
    "social-security",
    "retirement-budget",
    "retirement-income"
  ],
  "changelog": []
}