{
  "id": "diminished-value",
  "version": "7c393663ce4d",
  "status": "published",
  "name": "Diminished Value Calculator",
  "question": "What is my car’s diminished value?",
  "summary": "Estimates a car’s diminished value after an accident by the 17c formula: 10% of its pre-accident value, times a damage multiplier and a mileage multiplier.",
  "category": "finance",
  "subcategory": "loans",
  "url": "https://www.acalculator.org/finance/diminished-value-calculator",
  "markdown": "https://www.acalculator.org/finance/diminished-value-calculator.md",
  "kind": "function",
  "method": "Diminished value = value before the accident × 10% × damage multiplier × mileage multiplier. Mileage multiplier in steps: 1 − 0.2 × (whole 20,000-mile steps), 0 from 100,000 miles; on a straight line: 1 − miles ÷ 100,000, 0 from 100,000 miles.",
  "assumptions": [
    "The 17c formula is an insurer’s method from a Georgia class-action settlement; it is not a law, and a market appraisal often finds a larger loss.",
    "The value before the accident is the market value, which you look up and type.",
    "Whether you can claim diminished value, and from whom, depends on your state and policy."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "val": {
        "title": "Value before the accident",
        "description": "The car’s market value just before the accident, from a pricing guide or an appraisal.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000
      },
      "dmg": {
        "title": "Damage",
        "description": "How bad the structural damage was, which sets the damage multiplier.",
        "type": "string",
        "enum": [
          "1",
          "0.75",
          "0.5",
          "0.25",
          "0"
        ]
      },
      "mi": {
        "title": "Mileage",
        "description": "The miles on the odometer at the time of the accident.",
        "type": "number",
        "minimum": 0,
        "maximum": 2000000
      },
      "rule": {
        "title": "Mileage multiplier",
        "description": "Whether the mileage multiplier drops in 20,000-mile steps or on a straight line to 0 at 100,000 miles.",
        "type": "string",
        "enum": [
          "steps",
          "linear"
        ]
      }
    }
  },
  "outputs": {
    "dv": {
      "label": "Diminished value",
      "description": "Base loss × damage multiplier × mileage multiplier.",
      "format": "money"
    },
    "base": {
      "label": "Base loss (10% cap)",
      "description": "10% of the value before the accident.",
      "format": "money"
    },
    "damageMultiplier": {
      "label": "Damage multiplier",
      "description": "From the damage you chose.",
      "format": "number"
    },
    "mileageMultiplier": {
      "label": "Mileage multiplier",
      "description": "From the mileage and the rule you chose.",
      "format": "number"
    },
    "after": {
      "label": "Value after repair",
      "description": "The value before the accident minus the diminished value.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "val": 30000,
      "dmg": "0.5",
      "mi": 45000,
      "rule": "steps"
    },
    "outputs": {
      "dv": 900,
      "base": 3000,
      "damageMultiplier": 0.5,
      "mileageMultiplier": 0.6,
      "after": 29100
    },
    "text": "Diminished value by the 17c formula: $900.00 (10% base $3,000.00 × 0.5 × 0.6)."
  },
  "examples": [
    {
      "given": {
        "val": 30000,
        "dmg": "0.5",
        "mi": 45000,
        "rule": "steps"
      },
      "expect": {
        "base": 3000,
        "mileageMultiplier": 0.6,
        "dv": 900,
        "after": 29100
      },
      "source": "SnapClaim, Demystifying the Diminished Value 17c Calculator. https://snapclaim.com/diminished-value-17-c-calculator/ ($30,000 value, 10% = $3,000, moderate damage 0.50, 45,000 miles 0.60: $900)"
    },
    {
      "given": {
        "val": 21100,
        "dmg": "0.5",
        "mi": 43000,
        "rule": "linear"
      },
      "expect": {
        "base": 2110,
        "mileageMultiplier": 0.57,
        "dv": 601.35
      },
      "source": "17cformula.com, The 17c Formula (base loss 10% of value; damage modifiers 1.00 to 0.00; mileage modifiers 1.0 at 0 miles to 0.0 at 100,000+). https://17cformula.com/17c_diminished_value_formula_ebook.html (2010 MX-5 at 43,000 miles, $21,100: base $2,110, × 0.57, × 0.5 = $601, rounded); Python 3: Fraction(21100)/10*Fraction(57,100)/2 = 12027/20 = 601.35"
    },
    {
      "given": {
        "val": 150000,
        "dmg": "0.75",
        "mi": 25000,
        "rule": "steps"
      },
      "expect": {
        "base": 15000,
        "mileageMultiplier": 0.8,
        "dv": 9000
      },
      "source": "SuperCar Claims, 17c Formula. https://www.supercarclaims.com/17c-formula/ ($150,000, base $15,000, damage 0.75, mileage 0.80: $9,000)"
    },
    {
      "given": {
        "val": 40000,
        "dmg": "1",
        "mi": 120000,
        "rule": "steps"
      },
      "expect": {
        "mileageMultiplier": 0,
        "dv": 0,
        "after": 40000
      },
      "source": "17cformula.com, The 17c Formula (base loss 10% of value; damage modifiers 1.00 to 0.00; mileage modifiers 1.0 at 0 miles to 0.0 at 100,000+). https://17cformula.com/17c_diminished_value_formula_ebook.html (100,000+ miles: modifier 0.0)"
    }
  ],
  "sources": [
    "17cformula.com, The 17c Formula: What It Is, Why It’s Wrong & What Georgia Drivers Can Do (origin in State Farm v. Mabry; mileage modifiers 1.0 to 0.0 by 20,000 miles; damage modifiers 1.00 to 0.00; MX-5 example at 43,000 miles). https://17cformula.com/17c_diminished_value_formula_ebook.html (retrieved 2026-10-05)",
    "SnapClaim, Demystifying the Diminished Value 17c Calculator ($30,000 value, 0.50 damage, 0.60 at 45,000 miles: $900). https://snapclaim.com/diminished-value-17-c-calculator/ (retrieved 2026-10-05)",
    "SuperCar Claims, 17c Formula (pre-loss value × 10% × damage multiplier × mileage multiplier; $150,000 example: $9,000). https://www.supercarclaims.com/17c-formula/ (retrieved 2026-10-05)",
    "SecondAppraisal, Diminished value calculator (17c formula) (damage modifiers 1.00 severe, 0.75 major, 0.50 moderate, 0.25 minor, 0.00 none). https://secondappraisal.com/tools/diminished-value-calculator (retrieved 2026-10-05)"
  ],
  "related": [
    "car-depreciation",
    "auto-loan",
    "car-affordability",
    "car-sales-tax"
  ],
  "changelog": []
}