{
  "slug": "30x40-pole-barn-calculator",
  "title": "30x40 Pole Barn Calculator",
  "heading": "30x40 Pole Barn Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/30x40-pole-barn-calculator",
  "summary": "Posts, siding, and roofing estimates for a 30x40 pole barn shell.",
  "description": "A 30x40 pole barn is a popular size for a workshop, hobby garage, or equipment storage building. This calculator estimates the number of posts around the perimeter at a given spacing, the wall siding area, and the roof area based on your wall height and roof pitch, giving you a shopping list starting point and a rough material cost.",
  "formula": "Perimeter = 2 × (Length + Width). Posts = Perimeter ÷ Post Spacing. Wall Area = Perimeter × Wall Height. Roof Area = Length × Width × Pitch Factor.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=30x40-pole-barn-calculator",
  "inputs": [
    {
      "id": "length",
      "label": "Barn length",
      "kind": "number",
      "hint": null,
      "default": 40,
      "unit": "ft",
      "min": 10,
      "max": null
    },
    {
      "id": "width",
      "label": "Barn width",
      "kind": "number",
      "hint": null,
      "default": 30,
      "unit": "ft",
      "min": 10,
      "max": null
    },
    {
      "id": "wallHeight",
      "label": "Wall height",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "ft",
      "min": 8,
      "max": 20
    },
    {
      "id": "postSpacing",
      "label": "Post spacing",
      "kind": "number",
      "hint": null,
      "default": 8,
      "unit": "ft",
      "min": 4,
      "max": 12
    },
    {
      "id": "pricePerPost",
      "label": "Price per post",
      "kind": "number",
      "hint": null,
      "default": 40,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "posts",
      "label": "Perimeter posts needed",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "wallArea",
      "label": "Wall siding area (sq ft)",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "roofArea",
      "label": "Roof area (with pitch) (sq ft)",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "cost",
      "label": "Estimated post cost",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Barn length: 40 ft",
      "Barn width: 30 ft",
      "Wall height: 12 ft",
      "Post spacing: 8 ft",
      "Price per post: 40 $"
    ],
    "outputs": [
      "Perimeter posts needed: 18",
      "Wall siding area (sq ft): 1,680",
      "Roof area (with pitch) (sq ft): 1,380",
      "Estimated post cost: $720"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter barn length (ft).",
      "Enter barn width (ft).",
      "Enter wall height (ft).",
      "Enter post spacing (ft).",
      "Enter price per post ($).",
      "Read your perimeter posts 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": 25,
        "width": 20,
        "wallHeight": 8,
        "postSpacing": 5,
        "pricePerPost": 25
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "length": 40,
        "width": 30,
        "wallHeight": 12,
        "postSpacing": 8,
        "pricePerPost": 40
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "length": 65,
        "width": 50,
        "wallHeight": 19,
        "postSpacing": 12,
        "pricePerPost": 65
      }
    }
  ],
  "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 far apart should pole barn posts be spaced?",
      "a": "8 feet on center is a common default for light to moderate loads; wider spans need larger posts or additional engineering to handle snow and wind loads."
    },
    {
      "q": "How tall should a 30x40 pole barn be?",
      "a": "12 feet is typical for equipment or a workshop with a loft; go higher if you need to fit an RV or tall machinery inside."
    },
    {
      "q": "Does this calculator include the concrete floor?",
      "a": "No, use a dedicated slab calculator for the floor — this tool covers the post frame, wall siding, and roof area only."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/30x40-concrete-slab-calculator",
    "https://www.revenuelab.fyi/toolbox/24x24-garage-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — 30x40 Pole Barn Calculator (https://www.revenuelab.fyi/toolbox/30x40-pole-barn-calculator)"
}