{
  "id": "mulch",
  "version": "005b3847653d",
  "status": "published",
  "name": "Mulch Calculator",
  "question": "How much mulch do I need?",
  "summary": "Computes the mulch for an area at a chosen depth, with a waste allowance, in cubic yards, cubic feet, cubic metres and bags, and its weight and cost.",
  "category": "construction",
  "url": "https://www.acalculator.org/construction/mulch-calculator",
  "markdown": "https://www.acalculator.org/construction/mulch-calculator.md",
  "kind": "function",
  "method": "volume = area × depth × (1 + waste ÷ 100); weight = volume × density; bags = volume ÷ bag size, rounded up",
  "assumptions": [
    "The waste allowance is added to the volume before the bags, weight and cost are worked out.",
    "Bags are counted whole: 2 cu ft and 3 cu ft bags, and 60 L bags when the price is per 60 L bag.",
    "The typical densities are loose, dry bulk densities: wood chips 25 lb/ft³, bark 15, ground rubber 37.5 and gravel 105. Wet mulch weighs more. Pine straw and compost have no published value, so type one to see a weight.",
    "Weight is in US short tons of 2,000 lb."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "areaType": {
        "title": "Area",
        "description": "Whether you know the total area or the length and width.",
        "type": "string",
        "enum": [
          "total-area",
          "dimensions"
        ]
      },
      "area": {
        "title": "Total area",
        "description": "The area to cover with mulch.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "area",
        "exclusiveMinimum": 0,
        "maximum": 10000000
      },
      "len": {
        "title": "Length",
        "description": "The length of the bed.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 100000
      },
      "wid": {
        "title": "Width",
        "description": "The width of the bed.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 100000
      },
      "dep": {
        "title": "Depth",
        "description": "How thick the layer of mulch is. 2 to 4 inches is usual.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "exclusiveMinimum": 0,
        "maximum": 10
      },
      "mulchType": {
        "title": "Mulch type",
        "description": "The kind of mulch, which sets its typical weight per cubic foot.",
        "type": "string",
        "enum": [
          "wood-chips",
          "bark-mulch",
          "rubber-mulch",
          "stone-mulch",
          "pine-straw",
          "compost"
        ]
      },
      "wasteFactor": {
        "title": "Waste and settling",
        "description": "Extra mulch for waste and settling, as a percent of the volume.",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 100
      },
      "density": {
        "title": "Mulch density",
        "description": "The weight of one cubic foot of the mulch. Leave empty to use the typical density of the chosen type.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "density",
        "exclusiveMinimum": 0,
        "maximum": 5000
      },
      "price": {
        "title": "Price",
        "description": "The price of the mulch per volume unit or per bag. Leave empty to skip the cost.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 100000
      },
      "priceUnit": {
        "title": "Price is",
        "description": "What the price is for: a volume unit or one bag.",
        "type": "string",
        "enum": [
          "per-cubic-yard",
          "per-cubic-foot",
          "per-cubic-meter",
          "per-2-cubic-foot-bag",
          "per-3-cubic-foot-bag",
          "per-60-liter-bag"
        ]
      }
    }
  },
  "outputs": {
    "cubicYards": {
      "label": "Mulch to order",
      "description": "The volume to order, waste included: area × depth × (1 + waste ÷ 100).",
      "format": "quantity",
      "unit": "yd3"
    },
    "cubicFeet": {
      "label": "Cubic feet",
      "description": "The volume to order in cubic feet.",
      "format": "quantity",
      "unit": "ft3"
    },
    "cubicMeters": {
      "label": "Cubic metres",
      "description": "The volume to order in cubic metres.",
      "format": "quantity",
      "unit": "m3"
    },
    "bags2": {
      "label": "2 cu ft bags",
      "description": "Whole 2 cubic foot bags that hold the volume to order.",
      "format": "integer"
    },
    "bags3": {
      "label": "3 cu ft bags",
      "description": "Whole 3 cubic foot bags that hold the volume to order.",
      "format": "integer"
    },
    "bags60": {
      "label": "60 L bags",
      "description": "Whole 60 litre bags that hold the volume to order.",
      "format": "integer"
    },
    "coverage": {
      "label": "Area covered",
      "description": "The area the mulch covers, before the waste allowance.",
      "format": "quantity",
      "unit": "ft2"
    },
    "weight": {
      "label": "Weight",
      "description": "The volume to order × the mulch density, in US short tons of 2,000 lb.",
      "format": "quantity",
      "unit": "ton"
    },
    "tonnes": {
      "label": "Weight (metric)",
      "description": "The same weight in metric tonnes (1,000 kg).",
      "format": "quantity",
      "unit": "t"
    },
    "cost": {
      "label": "Estimated cost",
      "description": "The volume to order in the price unit × the price; bags are counted whole.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "areaType": "total-area",
      "area": 9.290304,
      "len": 6.096,
      "wid": 1.524,
      "dep": 0.07619999999999999,
      "mulchType": "wood-chips",
      "wasteFactor": 10,
      "priceUnit": "per-cubic-yard"
    },
    "outputs": {
      "cubicYards": 0.7787132812800001,
      "cubicFeet": 0.7787132812800001,
      "cubicMeters": 0.7787132812800001,
      "bags2": 14,
      "bags3": 10,
      "bags60": 13,
      "coverage": 9.290304,
      "weight": 311.844754375,
      "tonnes": 311.844754375
    },
    "text": "100 ft² at 3 in deep needs 1.02 yd³ of mulch, waste included."
  },
  "examples": [
    {
      "given": {
        "areaType": "total-area",
        "area": 9.290304,
        "dep": 0.07619999999999999,
        "mulchType": "wood-chips",
        "wasteFactor": 10,
        "priceUnit": "per-cubic-yard"
      },
      "expect": {
        "cubicFeet": 0.7787132812800002,
        "bags2": 14,
        "bags3": 10,
        "weight": 311.84475437500004
      },
      "source": "hand calculation in content.mdx: 100 × 0.25 × 1.1 = 27.5 ft³ = 1.02 yd³; 27.5 ÷ 2 → 14 bags; 27.5 × 25 lb = 687.5 lb; Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html"
    },
    {
      "given": {
        "areaType": "dimensions",
        "len": 6.096,
        "wid": 1.524,
        "dep": 0.07619999999999999,
        "mulchType": "wood-chips",
        "wasteFactor": 10,
        "price": 4,
        "priceUnit": "per-2-cubic-foot-bag"
      },
      "expect": {
        "cubicFeet": 0.7787132812800002,
        "cost": 56
      },
      "source": "hand calculation in content.mdx: 20 × 5 = 100 ft²; 27.5 ft³ needs 14 bags of 2 cu ft; 14 × $4 = $56; Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html"
    },
    {
      "given": {
        "areaType": "total-area",
        "area": 46.45152,
        "dep": 0.0508,
        "mulchType": "bark-mulch",
        "wasteFactor": 0,
        "price": 35,
        "priceUnit": "per-cubic-yard"
      },
      "expect": {
        "cubicYards": 2.359737216,
        "cost": 108.02469135802468,
        "weight": 566.9904625
      },
      "source": "hand calculation in content.mdx: 500 × 2/12 = 83.33 ft³ = 3.086 yd³; × $35 = $108.02; × 15 lb/ft³ = 1,250 lb; Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html"
    },
    {
      "given": {
        "areaType": "total-area",
        "area": 10,
        "dep": 0.05,
        "mulchType": "pine-straw",
        "wasteFactor": 0,
        "priceUnit": "per-60-liter-bag",
        "price": 6
      },
      "expect": {
        "cubicMeters": 0.5,
        "bags60": 9,
        "cost": 54
      },
      "source": "hand calculation in content.mdx: 10 m² × 0.05 m = 0.5 m³ = 500 L; 500 ÷ 60 → 9 bags; 9 × $6 = $54; Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³, bark 10 to 20 lb/ft³, ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html"
    }
  ],
  "sources": [
    "Engineering ToolBox, Densities of common Products (woodchips 20 to 30 lb/ft³; bark 10 to 20 lb/ft³; ground rubber 25 to 50 lb/ft³). https://www.engineeringtoolbox.com/density-materials-d_1652.html",
    "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement: 1 cubic yard = 27 cubic feet; 1 short ton = 2,000 pounds. https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
  ],
  "related": [],
  "changelog": [
    {
      "date": "2026-09-29",
      "note": "Any volume needs at least 1 bag; a tiny volume showed -0 bags and a -$0.00 cost (muse review)."
    },
    {
      "date": "2026-09-29",
      "note": "Worked examples name a published reference for their rule."
    }
  ]
}