{
  "slug": "16x20-deck-material-calculator",
  "title": "16x20 Deck Material Calculator",
  "heading": "16x20 Deck Material Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/16x20-deck-material-calculator",
  "summary": "Decking boards, joists, and cost for a 16x20 deck, pre-filled and editable.",
  "description": "16x20 is a popular larger deck size, often built to host a full outdoor dining and lounge area. This calculator defaults to those dimensions with 16-inch joist spacing and standard 5.5-inch boards, returning the board count, joist count, and total material cost, all fully editable for your actual layout.",
  "formula": "Deck Boards = (Width ÷ Board Coverage Width) × (1 + Waste%). Joists = (Length ÷ Joist Spacing) + 1. Cost = (Boards × Board Price) + (Joists × Joist Price).",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=16x20-deck-material-calculator",
  "inputs": [
    {
      "id": "length",
      "label": "Deck length",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "width",
      "label": "Deck width",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "joistSpacing",
      "label": "Joist spacing",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "in",
      "min": 12,
      "max": 24
    },
    {
      "id": "boardPrice",
      "label": "Price per deck board",
      "kind": "number",
      "hint": null,
      "default": 28,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "joistPrice",
      "label": "Price per joist",
      "kind": "number",
      "hint": null,
      "default": 22,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "waste",
      "label": "Waste factor",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 30
    }
  ],
  "outputs": [
    {
      "id": "boards",
      "label": "Deck boards needed",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "joists",
      "label": "Joists needed",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "cost",
      "label": "Estimated material cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "sqft",
      "label": "Deck square footage",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Deck length: 20 ft",
      "Deck width: 16 ft",
      "Joist spacing: 16 in",
      "Price per deck board: 28 $",
      "Price per joist: 22 $",
      "Waste factor: 10 %"
    ],
    "outputs": [
      "Deck boards needed: 39",
      "Joists needed: 16",
      "Estimated material cost: $1,444",
      "Deck square footage: 320"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter deck length (ft).",
      "Enter deck width (ft).",
      "Enter joist spacing (in).",
      "Enter price per deck board ($).",
      "Enter price per joist ($).",
      "Enter waste factor (%).",
      "Read your deck boards needed on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "length": 12,
        "width": 10,
        "joistSpacing": 12,
        "boardPrice": 17,
        "joistPrice": 13,
        "waste": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "length": 20,
        "width": 16,
        "joistSpacing": 16,
        "boardPrice": 28,
        "joistPrice": 22,
        "waste": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "length": 32,
        "width": 26,
        "joistSpacing": 24,
        "boardPrice": 45,
        "joistPrice": 35,
        "waste": 16
      }
    }
  ],
  "limitations": [
    "Estimates assume standard, average conditions — local rules, pricing, and materials vary.",
    "Results are rounded for readability; add a buffer before ordering, booking, or committing.",
    "Double-check anything with a real cost attached against a local quote."
  ],
  "faq": [
    {
      "q": "How big is a 16x20 deck in square feet?",
      "a": "320 square feet — large enough for a dining set, lounge area, and grill station, which is why it's one of the most requested deck sizes for full backyard builds."
    },
    {
      "q": "Do I need a beam in the middle of a 16x20 deck?",
      "a": "Likely yes — spans over roughly 12-14 feet usually require a center beam supported by posts and footings rather than a single joist run, so check your local span tables."
    },
    {
      "q": "How much lumber cost difference between composite and pressure-treated?",
      "a": "Composite boards typically run 2-3x the price of pressure-treated lumber per board but need no staining or sealing, so adjust the board price field to compare total costs for your material choice."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/12x16-deck-material-calculator",
    "https://www.revenuelab.fyi/toolbox/20x20-deck-material-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — 16x20 Deck Material Calculator (https://www.revenuelab.fyi/toolbox/16x20-deck-material-calculator)"
}