{
  "entity_type": "unit_conversion_page",
  "id": "acres-to-hectares",
  "name": "Acres to Hectares",
  "title": "Acres to Hectares Converter (acre to ha)",
  "description": "Convert acres to hectares: 1 acre = 0.404686 ha. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.",
  "quantity": "area",
  "quantity_name": "Area",
  "base_unit": "m2",
  "from_unit": {
    "symbol": "acre",
    "display": "acre",
    "name": "acres",
    "singular": "acre"
  },
  "to_unit": {
    "symbol": "ha",
    "display": "ha",
    "name": "hectares",
    "singular": "hectare"
  },
  "linear": true,
  "factor": 0.4046856422,
  "inverse_factor": 2.471053815,
  "formula": "hectares = acres × 0.4046856422",
  "reverse_formula": "acres = hectares × 2.471053815",
  "unit_relation": "1 acre = 0.404686 ha",
  "examples": [
    {
      "value": 5,
      "result": 2.02343,
      "text": "5 acre = 2.02343 ha"
    },
    {
      "value": 12.5,
      "result": 5.05857,
      "text": "12.5 acre = 5.05857 ha"
    },
    {
      "value": 100,
      "result": 40.4686,
      "text": "100 acre = 40.4686 ha"
    }
  ],
  "table": [
    {
      "acre": 1,
      "ha": 0.404686
    },
    {
      "acre": 2,
      "ha": 0.809371
    },
    {
      "acre": 3,
      "ha": 1.21406
    },
    {
      "acre": 4,
      "ha": 1.61874
    },
    {
      "acre": 5,
      "ha": 2.02343
    },
    {
      "acre": 6,
      "ha": 2.42811
    },
    {
      "acre": 7,
      "ha": 2.8328
    },
    {
      "acre": 8,
      "ha": 3.23749
    },
    {
      "acre": 9,
      "ha": 3.64217
    },
    {
      "acre": 10,
      "ha": 4.04686
    },
    {
      "acre": 15,
      "ha": 6.07028
    },
    {
      "acre": 20,
      "ha": 8.09371
    },
    {
      "acre": 25,
      "ha": 10.1171
    },
    {
      "acre": 30,
      "ha": 12.1406
    },
    {
      "acre": 40,
      "ha": 16.1874
    },
    {
      "acre": 50,
      "ha": 20.2343
    },
    {
      "acre": 75,
      "ha": 30.3514
    },
    {
      "acre": 100,
      "ha": 40.4686
    },
    {
      "acre": 200,
      "ha": 80.9371
    },
    {
      "acre": 250,
      "ha": 101.171
    },
    {
      "acre": 500,
      "ha": 202.343
    },
    {
      "acre": 1000,
      "ha": 404.686
    }
  ],
  "faq": [
    {
      "q": "How many hectares are in one acre?",
      "a": "1 acre = 0.404686 ha. 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 acres to hectares?",
      "a": "Multiply the value in acres by 0.4046856422: hectares = acres × 0.4046856422. For example, 5 acre = 2.02343 ha."
    },
    {
      "q": "How do I convert hectares back to acres?",
      "a": "Multiply by the inverse factor 2.471053815 (acres = hectares × 2.471053815), or use the hectares-to-acres 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=acre&to_unit=ha",
    "calculator": "https://tttkmbb.com/api/v1/calculate/area?value=5&from_unit=acre&to_unit=ha",
    "mcp_tool": "convert_units",
    "mcp_arguments": {
      "value": 5,
      "from_unit": "acre",
      "to_unit": "ha"
    }
  },
  "links": {
    "html": "https://tttkmbb.com/conversion/acres-to-hectares",
    "markdown": "https://tttkmbb.com/conversion/acres-to-hectares.md",
    "json": "https://tttkmbb.com/conversion/acres-to-hectares.json",
    "reverse": "https://tttkmbb.com/conversion/hectares-to-acres",
    "quantity_converter": "https://tttkmbb.com/conversion/area",
    "units": "https://tttkmbb.com/api/v1/units?quantity=area"
  },
  "timestamp": "2026-09-24"
}