{
  "id": "plywood",
  "version": "619ca1424786",
  "status": "published",
  "name": "Plywood Calculator",
  "question": "How many plywood sheets?",
  "summary": "Plywood calculator: how many 4 × 8 ft (or other) sheets of plywood or OSB cover a subfloor, wall or pitched roof deck, with waste and cost.",
  "category": "construction",
  "subcategory": "materials",
  "url": "https://www.acalculator.org/construction/plywood-calculator",
  "markdown": "https://www.acalculator.org/construction/plywood-calculator.md",
  "kind": "function",
  "method": "Sheets = length × width × slope factor × (1 + waste ÷ 100) ÷ sheet area, rounded up; slope factor = √(1 + (pitch ÷ 12)²) for a roof, 1 otherwise.",
  "assumptions": [
    "Offcuts are reused where they fit, so sheets are counted by area; waste covers what cannot be reused.",
    "A roof is measured in plan (from above), overhangs included; the slope factor turns that into the sloped area.",
    "Openings are not taken away; subtract them from the length or width if they are large."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "s": {
        "title": "Surface",
        "description": "A flat floor or wall, or a pitched roof measured in plan.",
        "type": "string",
        "enum": [
          "flat",
          "roof"
        ]
      },
      "l": {
        "title": "Length",
        "description": "The length of the floor or wall, or of the roof in plan with its overhangs.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 10000
      },
      "w": {
        "title": "Width",
        "description": "The width of the floor, the height of the wall, or the roof’s width in plan.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 10000
      },
      "pitch": {
        "title": "Roof pitch, rise in 12",
        "description": "Inches the roof rises for each 12 in of run, such as 6 for a 6/12 roof.",
        "type": "number",
        "minimum": 0,
        "maximum": 48
      },
      "sh": {
        "title": "Sheet size",
        "description": "The size of one sheet.",
        "type": "string",
        "enum": [
          "4x8",
          "4x9",
          "4x10",
          "5x5",
          "metric",
          "custom"
        ]
      },
      "sl": {
        "title": "Sheet length",
        "description": "The length of one sheet.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 10000
      },
      "sw": {
        "title": "Sheet width",
        "description": "The width of one sheet.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 10000
      },
      "x": {
        "title": "Waste",
        "description": "Extra for cuts, in percent.",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 100
      },
      "p": {
        "title": "Price per sheet",
        "description": "The price of one sheet. Leave empty to skip the cost.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000
      }
    }
  },
  "outputs": {
    "sheets": {
      "label": "Sheets to buy",
      "description": "Area × (1 + waste) ÷ sheet area, rounded up.",
      "format": "integer"
    },
    "area": {
      "label": "Area to cover",
      "description": "Length × width, × the roof slope factor for a roof.",
      "format": "quantity",
      "unit": "ft2"
    },
    "exactSheets": {
      "label": "Sheets without waste",
      "description": "Area ÷ sheet area, before rounding.",
      "format": "number"
    },
    "factor": {
      "label": "Roof slope factor",
      "description": "√(1 + (rise ÷ 12)²); 1 for a floor or wall.",
      "format": "number"
    },
    "cost": {
      "label": "Cost",
      "description": "Sheets to buy × the price per sheet.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "s": "flat",
      "l": 7.315200000000001,
      "w": 4.8768,
      "pitch": 6,
      "sh": "4x8",
      "sl": 2.4384,
      "sw": 1.2192,
      "x": 10
    },
    "outputs": {
      "sheets": 14,
      "area": 35.67476736,
      "exactSheets": 12,
      "factor": 1
    },
    "text": "Sheets of plywood to buy: 14, for 384 ft²."
  },
  "examples": [
    {
      "given": {
        "s": "flat",
        "l": 7.315200000000001,
        "w": 4.8768,
        "sh": "4x8",
        "x": 10,
        "p": 45
      },
      "expect": {
        "sheets": 14,
        "exactSheets": 12,
        "cost": 630
      },
      "source": "Wikipedia, Plywood (the most commonly used sheets are 4 by 8 ft, 1,220 × 2,440 mm; 1,200 × 2,400 mm is a common metric size; 5 × 5 ft is common for Baltic birch), https://en.wikipedia.org/wiki/Plywood (retrieved 2026-10-03); hand calculation in content.mdx: 24 × 16 = 384 ft² ÷ 32 = 12 sheets × 1.1 = 13.2, so 14; × $45 = $630",
      "tolerance": 1e-12
    },
    {
      "given": {
        "s": "roof",
        "l": 12.192,
        "w": 9.144,
        "pitch": 9,
        "sh": "4x8",
        "x": 0
      },
      "expect": {
        "factor": 1.25,
        "area": 139.35456000000002,
        "sheets": 47
      },
      "source": "Wikipedia, Plywood (the most commonly used sheets are 4 by 8 ft, 1,220 × 2,440 mm; 1,200 × 2,400 mm is a common metric size; 5 × 5 ft is common for Baltic birch), https://en.wikipedia.org/wiki/Plywood (retrieved 2026-10-03); hand calculation in content.mdx: √(1 + 0.75²) = 1.25; 1,200 × 1.25 = 1,500 ft² ÷ 32 = 46.875, so 47",
      "tolerance": 1e-12
    },
    {
      "given": {
        "s": "flat",
        "l": 4.8,
        "w": 2.4,
        "sh": "metric",
        "x": 0
      },
      "expect": {
        "sheets": 4,
        "exactSheets": 4
      },
      "source": "Wikipedia, Plywood (the most commonly used sheets are 4 by 8 ft, 1,220 × 2,440 mm; 1,200 × 2,400 mm is a common metric size; 5 × 5 ft is common for Baltic birch), https://en.wikipedia.org/wiki/Plywood (retrieved 2026-10-03); hand calculation in content.mdx: 4.8 × 2.4 = 11.52 m² ÷ 2.88 = 4 sheets exactly"
    },
    {
      "given": {
        "s": "roof",
        "l": 12.192,
        "w": 9.144,
        "pitch": 6,
        "sh": "4x8",
        "x": 10
      },
      "expect": {
        "factor": 1.118033988749895,
        "sheets": 47
      },
      "source": "Wikipedia, Plywood (the most commonly used sheets are 4 by 8 ft, 1,220 × 2,440 mm; 1,200 × 2,400 mm is a common metric size; 5 × 5 ft is common for Baltic birch), https://en.wikipedia.org/wiki/Plywood (retrieved 2026-10-03); hand calculation in content.mdx: √(1 + 0.5²) = 1.1180; 1,200 × 1.1180 = 1,341.6 ft² ÷ 32 = 41.93 × 1.1 = 46.12, so 47",
      "tolerance": 1e-12
    }
  ],
  "sources": [
    "Wikipedia, Plywood: the most commonly used sheets are 4 by 8 ft (1,220 × 2,440 mm); 1,200 × 2,400 mm is a common metric size; 5 × 5 ft is common for Baltic birch, retrieved 2026-10-03. https://en.wikipedia.org/wiki/Plywood",
    "NIST Special Publication 811 (2008), Appendix B: 1 ft = 0.3048 m exactly, 1 ft² = 0.09290304 m², retrieved 2026-10-03. https://www.nist.gov/pml/special-publication-811"
  ],
  "related": [
    "drywall",
    "roofing",
    "deck"
  ],
  "changelog": []
}