{
  "id": "siding",
  "version": "62b6355adca6",
  "status": "published",
  "name": "Siding Calculator",
  "question": "How much siding do I need?",
  "summary": "Computes the siding a house needs: the wall and gable area less doors and windows, in squares, and the vinyl panels and cartons or fiber cement planks to buy, with waste.",
  "category": "construction",
  "subcategory": "materials",
  "url": "https://www.acalculator.org/construction/siding-calculator",
  "markdown": "https://www.acalculator.org/construction/siding-calculator.md",
  "kind": "function",
  "method": "Area = wall length × wall height + gables × width × height ÷ 2 − doors and windows; squares = area ÷ 100 ft²; pieces = ⌈area × (1 + waste ÷ 100) ÷ (exposure × piece length)⌉; vinyl cartons = ⌈pieces ÷ 24⌉.",
  "assumptions": [
    "Walls are rectangles of one height; each gable is a triangle.",
    "Vinyl double 4 in panels show 8 in and are 12 ft 6 in long, 24 to a carton (2 squares); fiber cement 8.25 in planks show 7 in and are 12 ft long. Other products: type the exposure and length.",
    "Waste is 10% by default. Trim, corners, starter strip, J-channel and soffit are not counted."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "p": {
        "title": "Total wall length",
        "description": "The length of all the walls to side, added up (the house perimeter).",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 1000
      },
      "h": {
        "title": "Wall height",
        "description": "The height of the walls from the bottom of the siding to the eaves.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 100
      },
      "gab": {
        "title": "Gables",
        "description": "How many triangular gable ends sit above the walls.",
        "type": "integer",
        "minimum": 0,
        "maximum": 50
      },
      "gw": {
        "title": "Gable width",
        "description": "The width of one gable at its base.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 1000
      },
      "gh": {
        "title": "Gable height",
        "description": "The height of one gable from its base to the peak.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 100
      },
      "open": {
        "title": "Doors and windows",
        "description": "The total area of the doors and windows in these walls, which takes no siding.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "area",
        "minimum": 0,
        "maximum": 100000
      },
      "type": {
        "title": "Siding",
        "description": "The siding product, which sets how much wall one piece covers.",
        "type": "string",
        "enum": [
          "vinyl",
          "plank",
          "custom"
        ]
      },
      "exp": {
        "title": "Exposure",
        "description": "The height of one piece that shows on the wall once it is lapped.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.001,
        "maximum": 2
      },
      "len": {
        "title": "Piece length",
        "description": "The length of one piece of siding.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "length",
        "minimum": 0.01,
        "maximum": 20
      },
      "waste": {
        "title": "Extra for waste",
        "description": "Siding to add, in percent, for cuts at corners, openings and gables.",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 100
      }
    }
  },
  "outputs": {
    "pieces": {
      "label": "Pieces to buy",
      "description": "The area with waste ÷ the area one piece covers, rounded up.",
      "format": "integer"
    },
    "cartons": {
      "label": "Cartons",
      "description": "Pieces ÷ 24 per carton for the vinyl panels, rounded up.",
      "format": "integer"
    },
    "area": {
      "label": "Area to side",
      "description": "Walls + gables − doors and windows.",
      "format": "quantity",
      "unit": "ft2"
    },
    "squares": {
      "label": "Squares",
      "description": "The area in squares of 100 ft².",
      "format": "number"
    },
    "squaresWithWaste": {
      "label": "Squares with waste",
      "description": "The area with the extra for waste, in squares of 100 ft².",
      "format": "number"
    },
    "cover": {
      "label": "Covered by one piece",
      "description": "Exposure × piece length.",
      "format": "quantity",
      "unit": "ft2"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "p": 42.672000000000004,
      "h": 2.7432000000000003,
      "gab": 2,
      "gw": 9.144,
      "gh": 2.4384,
      "open": 13.935456,
      "type": "vinyl",
      "exp": 0.17779999999999999,
      "len": 3.6576000000000004,
      "waste": 10
    },
    "outputs": {
      "pieces": 179,
      "cartons": 8,
      "area": 125.419104,
      "squares": 13.5,
      "squaresWithWaste": 14.85,
      "cover": 0.7741920000000001
    },
    "text": "1,350 ft² of wall takes 179 pieces of siding (14.85 squares with waste)."
  },
  "examples": [
    {
      "given": {
        "p": 42.672000000000004,
        "h": 2.7432000000000003,
        "gab": 2,
        "gw": 9.144,
        "gh": 2.4384,
        "open": 13.935456,
        "type": "vinyl",
        "waste": 10
      },
      "expect": {
        "pieces": 179,
        "cartons": 8,
        "squares": 13.5,
        "squaresWithWaste": 14.85
      },
      "source": "CertainTeed Monogram vinyl siding, double 4 in (https://www.certainteed.com/products/siding-products/monogram, retrieved 2026-10-01), sold 24 panels of 12 ft 6 in to a carton (https://builderswarehouse.com/certainteed-monogram-double-4-siding-126-24-carton.html): 24 × 8 in × 12.5 ft = 200 ft², 2 squares; hand calculation in content.mdx: 1,350 ft² × 1.1 ÷ 8.333 = 178.2, so 179 pieces, 8 cartons"
    },
    {
      "given": {
        "p": 42.672000000000004,
        "h": 2.7432000000000003,
        "gab": 2,
        "gw": 9.144,
        "gh": 2.4384,
        "open": 13.935456,
        "type": "plank",
        "waste": 10
      },
      "expect": {
        "pieces": 213
      },
      "source": "James Hardie HardiePlank lap siding (https://www.jameshardie.com/product-catalog/exterior-siding-products/hardie-plank-lap-siding/, retrieved 2026-10-01), 8.25 in × 144 in planks (https://www.lowes.com/pd/James-Hardie-8-25-in-x-144-in-HZ5-HardiePlank-Cedarmill-Lap-Siding/999968871) with a 7 in exposure; hand calculation in content.mdx: 1,485 ÷ 7 = 212.1, so 213"
    },
    {
      "given": {
        "p": 30.48,
        "h": 2.4384,
        "gab": 0,
        "open": 0,
        "type": "plank",
        "waste": 0
      },
      "expect": {
        "pieces": 115,
        "squares": 8
      },
      "source": "James Hardie HardiePlank lap siding, 8.25 in plank with a 7 in exposure, listed at 14.3 pieces per square (https://www.lowes.com/pd/James-Hardie-8-25-in-x-144-in-HZ5-HardiePlank-Cedarmill-Lap-Siding/999968871); hand calculation in content.mdx: 800 ÷ 7 = 114.29, so 115"
    }
  ],
  "sources": [
    "James Hardie, HardiePlank lap siding product page (8.25 in planks, 12 ft, 7 in exposure), retrieved 2026-10-01. https://www.jameshardie.com/product-catalog/exterior-siding-products/hardie-plank-lap-siding/",
    "HardiePlank 8.25 in × 144 in lap siding listing (7 in exposure, 14.3 pieces per square), Lowe’s, retrieved 2026-10-01. https://www.lowes.com/pd/James-Hardie-8-25-in-x-144-in-HZ5-HardiePlank-Cedarmill-Lap-Siding/999968871",
    "CertainTeed, Monogram vinyl siding product page (double 4 in clapboard profile), retrieved 2026-10-01. https://www.certainteed.com/products/siding-products/monogram",
    "CertainTeed Monogram double 4 in siding, 12 ft 6 in, 24 per carton, listing at Builders Warehouse, retrieved 2026-10-01. https://builderswarehouse.com/certainteed-monogram-double-4-siding-126-24-carton.html"
  ],
  "related": [
    "roofing",
    "paint",
    "square-footage"
  ],
  "changelog": []
}