{
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  "category": "other",
  "question": "What is 180 degrees C in the other temperature scale, the nearest gas mark, and the fan-oven adjusted temperature?",
  "answer": "180 C / 356 F, gas mark 4, fan oven 160 C",
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  "validUntil": null,
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  "sources": [
    {
      "label": "Standard Fahrenheit/Celsius/gas mark oven temperature table",
      "url": null
    },
    {
      "label": "Oven Temperature Conversion Table",
      "url": "https://www.which.co.uk/reviews/built-in-ovens/article/oven-temperature-conversion-table-aA5Ol9b157On"
    }
  ],
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  "source": {
    "kind": "edition_page",
    "value": "Rombauer IS, Becker MR, Becker E. The Joy of Cooking, 2006 edition, oven temperature and gas mark conversion table, p. 3.",
    "retrieved_utc": "2026-09-30T19:55:00Z"
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  "method": {
    "name": "Oven temperature conversion",
    "version": "1",
    "source_url_or_file": "methods/oven-temperature-conversion.cjs",
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  "method_deck": {
    "inputs": [
      {
        "name": "temperature",
        "type": "number",
        "required": true,
        "description": "Oven temperature value"
      },
      {
        "name": "unit",
        "type": "string",
        "required": true,
        "description": "Unit of the given temperature",
        "enum": [
          "F",
          "C"
        ]
      }
    ],
    "outputs": [
      {
        "name": "celsius",
        "unit": "C",
        "description": "Temperature in Celsius"
      },
      {
        "name": "fahrenheit",
        "unit": "F",
        "description": "Temperature in Fahrenheit"
      },
      {
        "name": "gas_mark",
        "unit": null,
        "description": "Nearest UK gas mark from the cited table"
      },
      {
        "name": "fan_oven_celsius",
        "unit": "C",
        "description": "Suggested fan (convection) oven temperature, conventional minus 20 C"
      }
    ],
    "steps": [
      "If given in Fahrenheit: celsius = (fahrenheit - 32) * 5 / 9. If given in Celsius: fahrenheit = celsius * 9 / 5 + 32.",
      "Round celsius and fahrenheit to the nearest whole degree.",
      "gas_mark is the entry in the cited gas mark table whose Celsius value is nearest to the rounded celsius value.",
      "Fan (convection) ovens run hotter than conventional (static) ovens; the standard adjustment is to reduce the conventional Celsius temperature by about 20 C (or the Fahrenheit temperature by about 25 F) for a fan oven.",
      "fan_oven_celsius = celsius - 20, rounded to the nearest whole degree."
    ],
    "constants": [
      {
        "name": "gas_mark_1_4_c",
        "value": 110,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_1_2_c",
        "value": 120,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_1_c",
        "value": 140,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_2_c",
        "value": 150,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_3_c",
        "value": 170,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_4_c",
        "value": 180,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_5_c",
        "value": 190,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_6_c",
        "value": 200,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_7_c",
        "value": 220,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_8_c",
        "value": 230,
        "unit": "C",
        "source": 0
      },
      {
        "name": "gas_mark_9_c",
        "value": 240,
        "unit": "C",
        "source": 0
      },
      {
        "name": "fan_oven_reduction_c",
        "value": 20,
        "unit": "C",
        "source": 1
      }
    ],
    "examples": [
      {
        "name": "worked example",
        "inputs": {
          "temperature": 180,
          "unit": "C"
        },
        "expected": {
          "answer": "180 C / 356 F, gas mark 4, fan oven 160 C"
        },
        "check": "180*9/5+32 = 324+32 = 356. Nearest gas mark table entry to 180 C is gas mark 4 (180 C) exactly. Fan oven = 180-20 = 160."
      },
      {
        "name": "test vector: Fahrenheit input",
        "inputs": {
          "temperature": 425,
          "unit": "F"
        },
        "expected": {
          "answer": "218 C / 425 F, gas mark 7, fan oven 198 C"
        },
        "check": "(425-32)*5/9 = 393*5/9 = 218.333, rounds to 218. Nearest gas mark table entry to 218 C is gas mark 7 (220 C), diff 2, closer than gas mark 6 (200 C, diff 18). Fan oven = 218-20 = 198."
      }
    ],
    "disclaimer": null,
    "deck_category": "cooking"
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          "value": "Rombauer IS, Becker MR, Becker E. The Joy of Cooking, 2006 edition, oven temperature and gas mark conversion table, p. 3.",
          "retrieved_utc": "2026-09-30T19:55:00Z"
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        "added_utc": "2026-09-30T22:39:30.722Z",
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}