{
  "$comment": "Machine-readable companion to https://valem.run/calculators/japan/car-tax. Formula, inputs, outputs, engine-verified test vectors, cited sources and the re-runnable Valem ModelSpec behind the page.",
  "url": "https://valem.run/calculators/japan/car-tax",
  "dataUrl": "https://valem.run/calculators/japan/car-tax.json",
  "license": {
    "name": "CC BY 4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Japan 自動車税 model by Valem (https://valem.run/calculators/japan/car-tax), CC BY 4.0.",
    "note": "Covers the model — the expression of each rule and the arrangement of the catalog. The rates and thresholds themselves are law and are not licensed by anyone; the cited sources are where they come from."
  },
  "verificationUrl": "https://valem.run/calculators/japan/car-tax/verify",
  "country": "japan",
  "countryName": "Japan",
  "formula": "car-tax",
  "formulaName": "自動車税",
  "title": "自動車税 — Japan car tax",
  "answer": "Japan's annual automobile tax for cars registered from Oct 2019 is set by engine displacement bands.",
  "lang": "en",
  "currency": "JPY",
  "taxYear": "2026",
  "verification": {
    "claim": "internal-consistency",
    "statement": "The Valem engine reproduces this model's stated formula through 3 self-test cases (below, and re-runnable against the spec). That asserts internal consistency, NOT that the formula matches current law — the cited sources are the evidence for that, and carry the date each was last checked.",
    "selfTestCases": 3,
    "ratesAreIllustrative": false,
    "sourcesCheckedOn": "2026-08-02"
  },
  "sources": [
    {
      "label": "総務省 — 自動車税",
      "url": "https://www.soumu.go.jp",
      "checked": "2026-08-05"
    }
  ],
  "terminalOutput": "tax",
  "inputs": [
    {
      "name": "cc",
      "type": "number",
      "label": "排気量 (cc)",
      "minimum": 0
    },
    {
      "name": "ageYears",
      "type": "number",
      "label": "初度登録からの年数",
      "minimum": 0
    }
  ],
  "outputs": [
    {
      "name": "baseTax",
      "type": "number",
      "label": "自動車税（排気量別）",
      "format": "currency",
      "formula": "($c := cc; $round($c <= 1000 ? 25000 : $c <= 1500 ? 30500 : $c <= 2000 ? 36000 : $c <= 2500 ? 43500 : $c <= 3000 ? 50000 : $c <= 3500 ? 57000 : $c <= 4000 ? 65500 : $c <= 4500 ? 75500 : $c <= 6000 ? 87000 : 110000, 2))"
    },
    {
      "name": "oldCarSurcharge",
      "type": "number",
      "label": "13年超の重課",
      "format": "currency",
      "formula": "$round(ageYears >= $const.oldCarFromYear ? baseTax * $const.oldCarRate : 0, 2)"
    },
    {
      "name": "tax",
      "type": "number",
      "label": "年額",
      "format": "currency",
      "formula": "$round(baseTax + oldCarSurcharge, 2)"
    }
  ],
  "testCases": [
    {
      "description": "C1 1,496 cc, 3年 — 標準税額",
      "given": {
        "cc": 1496,
        "ageYears": 3
      },
      "expect": {
        "baseTax": 30500,
        "oldCarSurcharge": 0,
        "tax": 30500
      }
    },
    {
      "description": "C2 2,494 cc, 3年",
      "given": {
        "cc": 2494,
        "ageYears": 3
      },
      "expect": {
        "baseTax": 43500,
        "tax": 43500
      }
    },
    {
      "description": "C3 1,496 cc, 14年 — 13年超の重課15%",
      "given": {
        "cc": 1496,
        "ageYears": 14
      },
      "expect": {
        "oldCarSurcharge": 4575,
        "tax": 35075
      }
    }
  ],
  "spec": {
    "id": "car-tax-japan",
    "version": "1.0.0",
    "schema": {
      "type": "object",
      "properties": {
        "cc": {
          "type": "number",
          "minimum": 0
        },
        "ageYears": {
          "type": "number",
          "minimum": 0
        },
        "baseTax": {
          "type": "number",
          "readOnly": true
        },
        "oldCarSurcharge": {
          "type": "number",
          "readOnly": true
        },
        "tax": {
          "type": "number",
          "readOnly": true
        }
      }
    },
    "constants": {
      "oldCarRate": 0.15,
      "oldCarFromYear": 13
    },
    "defaultValues": [
      {
        "path": "$",
        "expr": "{ 'cc': 1496, 'ageYears': 3 }"
      }
    ],
    "derivations": [
      {
        "path": "$.baseTax",
        "expr": "($c := cc; $round($c <= 1000 ? 25000 : $c <= 1500 ? 30500 : $c <= 2000 ? 36000 : $c <= 2500 ? 43500 : $c <= 3000 ? 50000 : $c <= 3500 ? 57000 : $c <= 4000 ? 65500 : $c <= 4500 ? 75500 : $c <= 6000 ? 87000 : 110000, 2))"
      },
      {
        "path": "$.oldCarSurcharge",
        "expr": "$round(ageYears >= $const.oldCarFromYear ? baseTax * $const.oldCarRate : 0, 2)"
      },
      {
        "path": "$.tax",
        "expr": "$round(baseTax + oldCarSurcharge, 2)"
      }
    ],
    "constraints": [],
    "metaDerivations": [],
    "viewDefinition": {
      "renderer": "builtin",
      "defaultView": "main",
      "views": [
        {
          "id": "main",
          "label": "自動車税",
          "layout": "vertical",
          "components": [
            {
              "id": "cc",
              "type": "numericField",
              "label": "排気量 (cc)",
              "bind": "$.cc"
            },
            {
              "id": "age",
              "type": "numericField",
              "label": "初度登録からの年数",
              "bind": "$.ageYears"
            },
            {
              "id": "tiles",
              "type": "group",
              "layout": "horizontal",
              "components": [
                {
                  "id": "taxTile",
                  "type": "statTile",
                  "label": "年額",
                  "bind": "$.tax",
                  "format": "currency",
                  "currency": "JPY"
                }
              ]
            },
            {
              "id": "breakdown",
              "type": "keyValueList",
              "label": "内訳",
              "items": [
                {
                  "label": "自動車税（排気量別）",
                  "bind": "$.baseTax",
                  "format": "currency",
                  "currency": "JPY"
                },
                {
                  "label": "13年超の重課",
                  "bind": "$.oldCarSurcharge",
                  "format": "currency",
                  "currency": "JPY"
                },
                {
                  "label": "合計",
                  "bind": "$.tax",
                  "format": "currency",
                  "currency": "JPY"
                }
              ]
            },
            {
              "id": "note",
              "type": "staticText",
              "text": "'日本 2026年度: 自動車税（2019年10月以降の初度登録）は排気量で決まり、1,000cc以下の25,000円から6,000cc超の110,000円まで法定の税額表どおりです。初度登録から13年を超えるガソリン車は約15%の重課が加算されます（本計算に反映済み）。軽自動車は一律10,800円で別枠です。概算であり税務助言ではありません。'"
            },
            {
              "id": "sources",
              "type": "sourceList",
              "label": "出典",
              "items": [
                {
                  "label": "総務省 — 自動車税",
                  "url": "https://www.soumu.go.jp",
                  "date": "2026-08-05"
                }
              ]
            }
          ]
        }
      ]
    },
    "tests": [
      {
        "description": "C1 1,496 cc, 3年 — 標準税額",
        "given": {
          "$.cc": 1496,
          "$.ageYears": 3
        },
        "expect": {
          "$.baseTax": 30500,
          "$.oldCarSurcharge": 0,
          "$.tax": 30500
        }
      },
      {
        "description": "C2 2,494 cc, 3年",
        "given": {
          "$.cc": 2494,
          "$.ageYears": 3
        },
        "expect": {
          "$.baseTax": 43500,
          "$.tax": 43500
        }
      },
      {
        "description": "C3 1,496 cc, 14年 — 13年超の重課15%",
        "given": {
          "$.cc": 1496,
          "$.ageYears": 14
        },
        "expect": {
          "$.oldCarSurcharge": 4575,
          "$.tax": 35075
        }
      }
    ]
  }
}