{
  "slug": "rebar",
  "title": "Rebar Calculator",
  "heading": "Rebar Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/rebar",
  "summary": "Bar count, total length, and cost for a reinforcing grid.",
  "description": "Counts the bars in a two-way grid at your spacing, adds lap splices, and prices the order. Grid spacing is usually 12 to 18 inches on centre for residential slabs.",
  "formula": "Bars per direction = (Span ÷ Spacing) + 1, with lap length added per splice.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=rebar",
  "inputs": [
    {
      "id": "length",
      "label": "Slab length",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "ft",
      "min": 0,
      "max": null
    },
    {
      "id": "width",
      "label": "Slab width",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "ft",
      "min": 0,
      "max": null
    },
    {
      "id": "spacing",
      "label": "Grid spacing",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "in",
      "min": 2,
      "max": null
    },
    {
      "id": "barLength",
      "label": "Stock bar length",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "price",
      "label": "Price per foot",
      "kind": "number",
      "hint": null,
      "default": 0.75,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "sticks",
      "label": "Stock bars to buy",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "totalFeet",
      "label": "Total linear feet (incl. laps)",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "cost",
      "label": "Estimated cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "barsAcross",
      "label": "Bars running lengthwise",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "barsDown",
      "label": "Bars running widthwise",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Slab length: 20 ft",
      "Slab width: 12 ft",
      "Grid spacing: 16 in",
      "Stock bar length: 20 ft",
      "Price per foot: 0.75 $"
    ],
    "outputs": [
      "Stock bars to buy: 22",
      "Total linear feet (incl. laps): 423.36",
      "Estimated cost: $317.52",
      "Bars running lengthwise: 10",
      "Bars running widthwise: 16"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter slab length (ft).",
      "Enter slab width (ft).",
      "Enter grid spacing (in).",
      "Enter stock bar length (ft).",
      "Enter price per foot ($).",
      "Read your stock bars to buy 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": 7,
        "spacing": 10,
        "barLength": 12,
        "price": 0.44999999999999996
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "length": 20,
        "width": 12,
        "spacing": 16,
        "barLength": 20,
        "price": 0.75
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "length": 32,
        "width": 19,
        "spacing": 26,
        "barLength": 32,
        "price": 1.2000000000000002
      }
    }
  ],
  "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 rebar calculator work?",
      "a": "Counts the bars in a two-way grid at your spacing, adds lap splices, and prices the order. Grid spacing is usually 12 to 18 inches on centre for residential slabs. The underlying maths is: Bars per direction = (Span ÷ Spacing) + 1, with lap length added per splice."
    },
    {
      "q": "What do I need to enter?",
      "a": "5 values: slab length, slab width, grid spacing, stock bar length, and price per foot. 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 stock bars to buy result mean?",
      "a": "It is returned as a whole 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/concrete-slab",
    "https://www.revenuelab.fyi/toolbox/concrete-footing"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Rebar Calculator (https://www.revenuelab.fyi/toolbox/rebar)"
}