{
  "slug": "roof-solar-tilt",
  "title": "Solar Panel Tilt Calculator",
  "heading": "Optimal Solar Panel Tilt Calculator",
  "category": "math",
  "url": "https://www.revenuelab.fyi/toolbox/roof-solar-tilt",
  "summary": "Best fixed tilt angle for your latitude, by season.",
  "description": "A fixed array does best tilted near your latitude. Seasonal adjustments add roughly 15° in winter and subtract the same in summer.",
  "formula": "Winter ≈ lat + 15°, summer ≈ lat − 15°, annual ≈ lat × 0.87 + 3.1",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=roof-solar-tilt",
  "inputs": [
    {
      "id": "lat",
      "label": "Latitude",
      "kind": "number",
      "hint": null,
      "default": 37,
      "unit": "°",
      "min": 0,
      "max": 70
    }
  ],
  "outputs": [
    {
      "id": "annual",
      "label": "Year-round tilt (°)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "winter",
      "label": "Winter tilt (°)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "summer",
      "label": "Summer tilt (°)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "azimuth",
      "label": "Orientation",
      "format": "raw",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Latitude: 37 °"
    ],
    "outputs": [
      "Year-round tilt (°): 35.3",
      "Winter tilt (°): 52",
      "Summer tilt (°): 22",
      "Orientation: Face true south (north in S. hemisphere)"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter latitude (°).",
      "Read your year-round tilt (°) 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": {
        "lat": 22.2
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "lat": 37
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "lat": 59.2
      }
    }
  ],
  "limitations": [
    "Results are rounded for display; the underlying calculation keeps full precision.",
    "Very large or very small inputs may hit floating-point limits in the browser.",
    "Inputs outside the accepted range are clamped rather than rejected."
  ],
  "faq": [
    {
      "q": "How does the optimal solar panel tilt calculator work?",
      "a": "A fixed array does best tilted near your latitude. Seasonal adjustments add roughly 15° in winter and subtract the same in summer. The underlying maths is: Winter ≈ lat + 15°, summer ≈ lat − 15°, annual ≈ lat × 0.87 + 3.1"
    },
    {
      "q": "What do I need to enter?",
      "a": "Just one value: latitude. 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 year-round tilt (°) 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. Results are rounded for display; the underlying calculation keeps full precision."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/solar-savings"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Solar Panel Tilt Calculator (https://www.revenuelab.fyi/toolbox/roof-solar-tilt)"
}