{
  "slug": "stair-stringer",
  "title": "Stair Stringer Calculator",
  "heading": "Stair Rise, Run & Stringer Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/stair-stringer",
  "summary": "Riser height, tread depth, and stringer length from total rise.",
  "description": "Most codes cap riser height around 7.75 in and require at least a 10 in tread. Dividing total rise by 7 gets you close to a legal, comfortable stair.",
  "formula": "Risers = round(total rise ÷ target riser); stringer = √(rise² + run²).",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=stair-stringer",
  "inputs": [
    {
      "id": "rise",
      "label": "Total rise (floor to floor)",
      "kind": "number",
      "hint": null,
      "default": 108,
      "unit": "in",
      "min": 6,
      "max": null
    },
    {
      "id": "target",
      "label": "Target riser height",
      "kind": "number",
      "hint": null,
      "default": 7,
      "unit": "in",
      "min": 4,
      "max": 8
    },
    {
      "id": "tread",
      "label": "Tread depth",
      "kind": "number",
      "hint": null,
      "default": 10.5,
      "unit": "in",
      "min": 9,
      "max": 14
    }
  ],
  "outputs": [
    {
      "id": "riserH",
      "label": "Riser height (in)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "risers",
      "label": "Number of risers",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "treads",
      "label": "Number of treads",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "run",
      "label": "Total run (in)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "stringer",
      "label": "Stringer length (in)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "angle",
      "label": "Stair angle (degrees)",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Total rise (floor to floor): 108 in",
      "Target riser height: 7 in",
      "Tread depth: 10.5 in"
    ],
    "outputs": [
      "Riser height (in): 7.2",
      "Number of risers: 15",
      "Number of treads: 14",
      "Total run (in): 147",
      "Stringer length (in): 182.4",
      "Stair angle (degrees): 36.3"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter total rise (floor to floor) (in).",
      "Enter target riser height (in).",
      "Enter tread depth (in).",
      "Read your riser height (in) 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": {
        "rise": 64.8,
        "target": 4.2,
        "tread": 9
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "rise": 108,
        "target": 7,
        "tread": 10.5
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "rise": 172.8,
        "target": 8,
        "tread": 14
      }
    }
  ],
  "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 stair rise, run & stringer calculator work?",
      "a": "Most codes cap riser height around 7.75 in and require at least a 10 in tread. Dividing total rise by 7 gets you close to a legal, comfortable stair. The underlying maths is: Risers = round(total rise ÷ target riser); stringer = √(rise² + run²)."
    },
    {
      "q": "What do I need to enter?",
      "a": "3 values: total rise (floor to floor), target riser height, and tread depth. 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 riser height (in) 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/deck-board-calculator",
    "https://www.revenuelab.fyi/toolbox/roof-pitch"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Stair Stringer Calculator (https://www.revenuelab.fyi/toolbox/stair-stringer)"
}