{
  "id": "acreage",
  "version": "db0f939563d4",
  "status": "published",
  "name": "Acreage Calculator",
  "question": "What is the acreage of my land?",
  "summary": "Computes the acreage of a rectangular, triangular, trapezoid or circular plot from its measurements, or of an area typed in any unit, in acres, square feet, square yards, square metres and hectares.",
  "category": "construction",
  "url": "https://www.acalculator.org/construction/acreage-calculator",
  "markdown": "https://www.acalculator.org/construction/acreage-calculator.md",
  "kind": "function",
  "method": "Area = length × width (rectangle), ½ × base × height (triangle), ½ × (a + b) × height (trapezoid), or π × d² ÷ 4 (circle); acres = square feet ÷ 43,560.",
  "assumptions": [
    "The land is flat: the area is measured on a level plane, as a survey does, not along slopes.",
    "An acre is 43,560 square feet of the international foot, 4,046.8564224 m² exactly.",
    "A plot with an irregular shape can be split into rectangles, triangles and trapezoids, with the acreages added."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "shape": {
        "title": "Shape of the land",
        "description": "The shape of the plot, or \"I know the area\" to convert an area to acres.",
        "type": "string",
        "enum": [
          "rect",
          "tri",
          "trap",
          "circle",
          "area"
        ]
      },
      "l": {
        "title": "Length",
        "description": "The length of the rectangle.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "w": {
        "title": "Width",
        "description": "The width of the rectangle, at right angles to the length.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "b": {
        "title": "Base",
        "description": "The base of the triangle.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "a": {
        "title": "Top side",
        "description": "The first of the two parallel sides of the trapezoid.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "c": {
        "title": "Bottom side",
        "description": "The second of the two parallel sides of the trapezoid.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "h": {
        "title": "Height",
        "description": "The height of the triangle or trapezoid, at right angles to the base or the parallel sides.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "d": {
        "title": "Diameter",
        "description": "The diameter of the circle.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 1000000
      },
      "area": {
        "title": "Area",
        "description": "An area in any unit, to convert to acres.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "area",
        "exclusiveMinimum": 0,
        "maximum": 10000000000000
      }
    }
  },
  "outputs": {
    "acres": {
      "label": "Acres",
      "description": "The area in acres (1 acre = 43,560 square feet).",
      "format": "number"
    },
    "squareFeet": {
      "label": "Square feet",
      "description": "The area in square feet.",
      "format": "number"
    },
    "squareYards": {
      "label": "Square yards",
      "description": "The area in square yards (9 square feet each).",
      "format": "number"
    },
    "squareMeters": {
      "label": "Square metres",
      "description": "The area in square metres.",
      "format": "number"
    },
    "hectares": {
      "label": "Hectares",
      "description": "The area in hectares (10,000 square metres each).",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "shape": "rect",
      "l": 121.92,
      "w": 76.2,
      "b": 91.44,
      "a": 60.96,
      "c": 91.44,
      "h": 60.96,
      "d": 91.44,
      "area": 4046.8564224
    },
    "outputs": {
      "acres": 2.295684113865932,
      "squareFeet": 100000,
      "squareYards": 11111.111111111111,
      "squareMeters": 9290.304,
      "hectares": 0.9290304
    },
    "text": "In acres, the land measures 2.2957; in square feet, 100,000."
  },
  "examples": [
    {
      "given": {
        "shape": "rect",
        "l": 121.92,
        "w": 76.2
      },
      "expect": {
        "acres": 2.295684113865932,
        "squareFeet": 100000,
        "squareYards": 11111.111111111111,
        "squareMeters": 9290.304,
        "hectares": 0.9290304
      },
      "source": "NIST Handbook 44, Appendix C (1 acre = 43,560 ft², 1 ft = 0.3048 m); hand calculation in content.mdx: 400 × 250 = 100,000 ft² ÷ 43,560 = 2.2957 acres"
    },
    {
      "given": {
        "shape": "rect",
        "l": 201.168,
        "w": 20.1168
      },
      "expect": {
        "acres": 1,
        "squareFeet": 43560,
        "squareMeters": 4046.8564224
      },
      "source": "NIST Handbook 44, Appendix C: 1 furlong = 660 ft, 1 chain = 66 ft, 1 acre = 43,560 ft² = 4,046.8564224 m² (international foot)"
    },
    {
      "given": {
        "shape": "area",
        "area": 10000
      },
      "expect": {
        "acres": 2.4710538146716536,
        "hectares": 1,
        "squareFeet": 107639.10416709722
      },
      "source": "NIST Handbook 44, Appendix C (1 hectare = 10,000 m²; 1 acre = 4,046.8564224 m²); hand calculation in content.mdx: 10,000 ÷ 4,046.8564224 = 2.4711 acres"
    },
    {
      "given": {
        "shape": "tri",
        "b": 91.44,
        "h": 60.96
      },
      "expect": {
        "acres": 0.6887052341597796,
        "squareFeet": 30000
      },
      "source": "Triangle area ½ × base × height (OpenStax, Prealgebra 2e, §9.4); hand calculation in content.mdx"
    },
    {
      "given": {
        "shape": "trap",
        "a": 60.96,
        "c": 91.44,
        "h": 45.72
      },
      "expect": {
        "acres": 0.8608815426997245,
        "squareFeet": 37500
      },
      "source": "Trapezoid area ½ × (a + b) × h (OpenStax, Prealgebra 2e, §9.4); hand calculation in content.mdx: ½ × 500 × 150 = 37,500 ft²"
    },
    {
      "given": {
        "shape": "circle",
        "d": 100
      },
      "expect": {
        "squareMeters": 7853.981633974483,
        "acres": 1.940761127699375
      },
      "source": "Circle area π × d² ÷ 4 (OpenStax, Prealgebra 2e, §9.5); hand calculation in content.mdx"
    },
    {
      "given": {
        "shape": "rect",
        "l": 132.777518544,
        "w": 30.48
      },
      "expect": {
        "acres": 1.00005,
        "squareFeet": 43562.178
      },
      "source": "NIST Handbook 44, Appendix C (1 acre = 43,560 ft²); hand calculation in content.mdx: 43,562.178 ÷ 43,560"
    }
  ],
  "sources": [
    "NIST Handbook 44 (2024), Appendix C, General Tables of Units of Measurement: 1 acre = 43,560 ft² = 4,840 yd²; 1 furlong = 660 ft; 1 chain = 66 ft; 1 hectare = 10,000 m². https://www.nist.gov/pml/owm/nist-handbook-44-current-edition",
    "National Institute of Standards and Technology and NOAA, Deprecation of the United States Survey Foot, Federal Register 85 FR 62698 (2020): from 2023, US lengths and areas use the international foot, 1 ft = 0.3048 m exactly. https://www.federalregister.gov/d/2020-21902",
    "OpenStax, Prealgebra 2e, §9.4 Use Properties of Rectangles, Triangles, and Trapezoids, and §9.5 Solve Geometry Applications: Circles and Irregular Figures. https://openstax.org/books/prealgebra-2e/pages/9-4-use-properties-of-rectangles-triangles-and-trapezoids"
  ],
  "related": [
    "square-footage",
    "cubic-yards"
  ],
  "changelog": [
    {
      "date": "2026-09-30",
      "note": "Metric heads the result with hectares; the answer names hectares and m² first."
    }
  ]
}