{
  "slug": "roof-pitch",
  "title": "Roof Pitch Calculator",
  "heading": "Roof Pitch, Slope & Rafter Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/roof-pitch",
  "summary": "Convert pitch to degrees and get rafter length.",
  "description": "Pitch is rise over a 12 in run. A 6/12 roof rises 6 in per foot, which is about 26.6 degrees and walkable for most roofers.",
  "formula": "Angle = atan(rise ÷ 12); rafter = run × √(1 + (rise/12)²).",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=roof-pitch",
  "inputs": [
    {
      "id": "pitch",
      "label": "Rise per 12 in run",
      "kind": "number",
      "hint": null,
      "default": 6,
      "unit": "in",
      "min": 0.5,
      "max": 24
    },
    {
      "id": "span",
      "label": "Building span",
      "kind": "number",
      "hint": null,
      "default": 28,
      "unit": "ft",
      "min": 2,
      "max": null
    },
    {
      "id": "overhang",
      "label": "Overhang",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "in",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "angle",
      "label": "Roof angle (degrees)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "rafter",
      "label": "Rafter length (ft)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "rise",
      "label": "Ridge rise (ft)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "factor",
      "label": "Roof pitch multiplier",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "gradePct",
      "label": "Slope (%)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "area",
      "label": "Sloped area per ft of ridge",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Rise per 12 in run: 6 in",
      "Building span: 28 ft",
      "Overhang: 16 in"
    ],
    "outputs": [
      "Roof angle (degrees): 26.57",
      "Rafter length (ft): 16.99",
      "Ridge rise (ft): 7",
      "Roof pitch multiplier: 1.118",
      "Slope (%): 50",
      "Sloped area per ft of ridge: 31.3"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter rise per 12 in run (in).",
      "Enter building span (ft).",
      "Enter overhang (in).",
      "Read your roof angle (degrees) 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": {
        "pitch": 3.5999999999999996,
        "span": 17,
        "overhang": 10
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "pitch": 6,
        "span": 28,
        "overhang": 16
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "pitch": 9.600000000000001,
        "span": 45,
        "overhang": 26
      }
    }
  ],
  "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 does the roof pitch, slope & rafter calculator work?",
      "a": "Pitch is rise over a 12 in run. A 6/12 roof rises 6 in per foot, which is about 26.6 degrees and walkable for most roofers. The underlying maths is: Angle = atan(rise ÷ 12); rafter = run × √(1 + (rise/12)²)."
    },
    {
      "q": "What do I need to enter?",
      "a": "3 values: rise per 12 in run, building span, and overhang. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the roof angle (degrees) result mean?",
      "a": "It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/stair-stringer",
    "https://www.revenuelab.fyi/toolbox/gutter-sizing"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Roof Pitch Calculator (https://www.revenuelab.fyi/toolbox/roof-pitch)"
}