{
  "entity_type": "unit_conversion_page",
  "id": "kcal-to-kj",
  "name": "Kilocalories (food calories) to Kilojoules",
  "title": "Kilocalories (food calories) to Kilojoules Converter (kcal to kJ)",
  "description": "Convert kilocalories (food calories) to kilojoules: 1 kcal = 4.184 kJ. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.",
  "quantity": "energy",
  "quantity_name": "Energy",
  "base_unit": "J",
  "from_unit": {
    "symbol": "kcal",
    "display": "kcal",
    "name": "kilocalories (food calories)",
    "singular": "kilocalorie"
  },
  "to_unit": {
    "symbol": "kJ",
    "display": "kJ",
    "name": "kilojoules",
    "singular": "kilojoule"
  },
  "linear": true,
  "factor": 4.184,
  "inverse_factor": 0.2390057361,
  "formula": "kilojoules = kilocalories (food calories) × 4.184",
  "reverse_formula": "kilocalories (food calories) = kilojoules × 0.2390057361",
  "unit_relation": "1 kcal = 4.184 kJ",
  "examples": [
    {
      "value": 5,
      "result": 20.92,
      "text": "5 kcal = 20.92 kJ"
    },
    {
      "value": 12.5,
      "result": 52.3,
      "text": "12.5 kcal = 52.3 kJ"
    },
    {
      "value": 100,
      "result": 418.4,
      "text": "100 kcal = 418.4 kJ"
    }
  ],
  "table": [
    {
      "kcal": 1,
      "kJ": 4.184
    },
    {
      "kcal": 2,
      "kJ": 8.368
    },
    {
      "kcal": 3,
      "kJ": 12.552
    },
    {
      "kcal": 4,
      "kJ": 16.736
    },
    {
      "kcal": 5,
      "kJ": 20.92
    },
    {
      "kcal": 6,
      "kJ": 25.104
    },
    {
      "kcal": 7,
      "kJ": 29.288
    },
    {
      "kcal": 8,
      "kJ": 33.472
    },
    {
      "kcal": 9,
      "kJ": 37.656
    },
    {
      "kcal": 10,
      "kJ": 41.84
    },
    {
      "kcal": 15,
      "kJ": 62.76
    },
    {
      "kcal": 20,
      "kJ": 83.68
    },
    {
      "kcal": 25,
      "kJ": 104.6
    },
    {
      "kcal": 30,
      "kJ": 125.52
    },
    {
      "kcal": 40,
      "kJ": 167.36
    },
    {
      "kcal": 50,
      "kJ": 209.2
    },
    {
      "kcal": 75,
      "kJ": 313.8
    },
    {
      "kcal": 100,
      "kJ": 418.4
    },
    {
      "kcal": 200,
      "kJ": 836.8
    },
    {
      "kcal": 250,
      "kJ": 1046
    },
    {
      "kcal": 500,
      "kJ": 2092
    },
    {
      "kcal": 1000,
      "kJ": 4184
    }
  ],
  "faq": [
    {
      "q": "How many kilojoules are in one kilocalorie?",
      "a": "1 kcal = 4.184 kJ. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures."
    },
    {
      "q": "What is the formula to convert kilocalories (food calories) to kilojoules?",
      "a": "Multiply the value in kilocalories (food calories) by 4.184: kilojoules = kilocalories (food calories) × 4.184. For example, 5 kcal = 20.92 kJ."
    },
    {
      "q": "How do I convert kilojoules back to kilocalories (food calories)?",
      "a": "Multiply by the inverse factor 0.2390057361 (kilocalories (food calories) = kilojoules × 0.2390057361), or use the kilojoules-to-kilocalories (food calories) page."
    }
  ],
  "sources": [
    {
      "name": "NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors",
      "url": "https://www.nist.gov/pml/special-publication-811",
      "type": "standard",
      "retrieved_at": "2026-09-24"
    },
    {
      "name": "BIPM – The International System of Units (SI Brochure, 9th edition)",
      "url": "https://www.bipm.org/en/publications/si-brochure",
      "type": "standard",
      "retrieved_at": "2026-09-24"
    },
    {
      "name": "Wikipedia – Conversion of units",
      "url": "https://en.wikipedia.org/wiki/Conversion_of_units",
      "type": "reference",
      "retrieved_at": "2026-09-24"
    }
  ],
  "freshness": {
    "type": "static",
    "max_age_seconds": null,
    "note": "Fixed conversion factors (NIST/BIPM definitions); results never go stale."
  },
  "api": {
    "convert": "https://tttkmbb.com/api/v1/convert?value=5&from_unit=kcal&to_unit=kJ",
    "calculator": "https://tttkmbb.com/api/v1/calculate/energy?value=5&from_unit=kcal&to_unit=kJ",
    "mcp_tool": "convert_units",
    "mcp_arguments": {
      "value": 5,
      "from_unit": "kcal",
      "to_unit": "kJ"
    }
  },
  "links": {
    "html": "https://tttkmbb.com/conversion/kcal-to-kj",
    "markdown": "https://tttkmbb.com/conversion/kcal-to-kj.md",
    "json": "https://tttkmbb.com/conversion/kcal-to-kj.json",
    "reverse": "https://tttkmbb.com/conversion/kj-to-kcal",
    "quantity_converter": "https://tttkmbb.com/conversion/energy",
    "units": "https://tttkmbb.com/api/v1/units?quantity=energy"
  },
  "timestamp": "2026-09-24"
}