{
  "slug": "rebar-linear-feet-calculator",
  "title": "Rebar Linear Feet Calculator",
  "heading": "Rebar Linear Feet Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/rebar-linear-feet-calculator",
  "summary": "Total rebar length needed for a slab grid based on spacing in both directions.",
  "description": "Reinforcing a concrete slab or footing with rebar means laying a grid of bars running in both directions at a set spacing, commonly 12, 16, or 18 inches on-center depending on the load and local code requirements, and the total linear footage needed is the sum of every bar run in both the length and width directions. This calculator takes your slab's length and width, your on-center spacing, and edge clearance (rebar is typically kept 2-3 inches back from the slab edge), calculates how many bars run in each direction, multiplies by the run length, sums both directions, and adds a lap splice allowance since rebar comes in fixed stock lengths (commonly 20 feet) and adjacent bars need to overlap by roughly 12-24 inches (or per code, often 40× the bar diameter) at any splice point. It also converts total linear feet into the number of standard 20-foot stock lengths needed to buy, since that's how rebar is typically sold at a supply yard.",
  "formula": "Bars per direction = floor((Dimension − 2×Edge Clearance) ÷ Spacing) + 1. Total Length = Σ(bars × perpendicular run length) × (1 + Lap%).",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=rebar-linear-feet-calculator",
  "inputs": [
    {
      "id": "length",
      "label": "Slab length",
      "kind": "number",
      "hint": null,
      "default": 20,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "width",
      "label": "Slab width",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "spacingIn",
      "label": "Grid spacing",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "in",
      "min": 6,
      "max": 36
    },
    {
      "id": "edgeClearanceIn",
      "label": "Edge clearance",
      "kind": "number",
      "hint": null,
      "default": 3,
      "unit": "in",
      "min": 1,
      "max": 6
    },
    {
      "id": "lapPct",
      "label": "Lap splice allowance",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 25
    }
  ],
  "outputs": [
    {
      "id": "totalLinearFeet",
      "label": "Total rebar needed",
      "format": "decimal",
      "hint": "linear ft",
      "primary": true
    },
    {
      "id": "stockLengths20ft",
      "label": "20ft stock lengths to buy",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "barsAcrossWidth",
      "label": "Bars running lengthwise",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "barsAcrossLength",
      "label": "Bars running widthwise",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Slab length: 20 ft",
      "Slab width: 10 ft",
      "Grid spacing: 16 in",
      "Edge clearance: 3 in",
      "Lap splice allowance: 10 %"
    ],
    "outputs": [
      "Total rebar needed: 341",
      "20ft stock lengths to buy: 18",
      "Bars running lengthwise: 15",
      "Bars running widthwise: 8"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter slab length (ft).",
      "Enter slab width (ft).",
      "Enter grid spacing (in).",
      "Enter edge clearance (in).",
      "Enter lap splice allowance (%).",
      "Read your total rebar 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": 12,
        "width": 6,
        "spacingIn": 10,
        "edgeClearanceIn": 1.7999999999999998,
        "lapPct": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "length": 20,
        "width": 10,
        "spacingIn": 16,
        "edgeClearanceIn": 3,
        "lapPct": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "length": 32,
        "width": 16,
        "spacingIn": 26,
        "edgeClearanceIn": 4.800000000000001,
        "lapPct": 16
      }
    }
  ],
  "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": "What rebar spacing is standard for a slab?",
      "a": "12-18 inches on-center is common for residential slabs, with tighter spacing (12 in) used for driveways or slabs bearing vehicle loads and wider spacing (16-18 in) for patios and sheds."
    },
    {
      "q": "What size rebar should I use?",
      "a": "#3 (3/8 in) or #4 (1/2 in) rebar covers most residential slab and footing applications; heavier structural work or engineered designs may call for #5 or larger — check your local code or engineer's spec."
    },
    {
      "q": "How much overlap does rebar need at a splice?",
      "a": "A common rule of thumb is 40 times the bar's diameter, though many residential jobs use a simpler 12-24 inch overlap; always defer to your local code or engineer's specification where one applies."
    },
    {
      "q": "Do I need rebar or is wire mesh enough?",
      "a": "Wire mesh controls surface cracking in light-duty slabs like patios, while rebar provides real structural reinforcement for load-bearing slabs, footings, and anything supporting a structure or vehicle weight — check your code for which is required."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/wire-mesh-sheets-calculator",
    "https://www.revenuelab.fyi/toolbox/concrete-slab-20x20-calculator",
    "https://www.revenuelab.fyi/toolbox/concrete-cubic-yards-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Rebar Linear Feet Calculator (https://www.revenuelab.fyi/toolbox/rebar-linear-feet-calculator)"
}