{
  "slug": "concrete-footing",
  "title": "Concrete Footing Calculator",
  "heading": "Concrete Footing Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/concrete-footing",
  "summary": "Volume and cost for strip footings and pier holes.",
  "description": "Footings carry the structure, so they get poured to code depth below the frost line. Enter the trench dimensions or the pier diameter and count to get your order volume.",
  "formula": "Strip: Length × Width × Depth ÷ 27. Piers: π × r² × Depth × Count ÷ 27.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=concrete-footing",
  "inputs": [
    {
      "id": "type",
      "label": "Footing type",
      "kind": "select",
      "hint": null,
      "default": "strip",
      "options": [
        {
          "value": "strip",
          "label": "Continuous strip footing"
        },
        {
          "value": "pier",
          "label": "Round pier holes"
        }
      ]
    },
    {
      "id": "length",
      "label": "Trench length",
      "kind": "number",
      "hint": null,
      "default": 60,
      "unit": "ft",
      "min": 0,
      "max": null
    },
    {
      "id": "width",
      "label": "Trench width",
      "kind": "number",
      "hint": null,
      "default": 16,
      "unit": "in",
      "min": 1,
      "max": null
    },
    {
      "id": "depth",
      "label": "Depth",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "in",
      "min": 1,
      "max": null
    },
    {
      "id": "diameter",
      "label": "Pier diameter",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": "in",
      "min": 1,
      "max": null
    },
    {
      "id": "count",
      "label": "Number of piers",
      "kind": "number",
      "hint": null,
      "default": 8,
      "unit": null,
      "min": 0,
      "max": null
    },
    {
      "id": "price",
      "label": "Ready-mix price",
      "kind": "number",
      "hint": null,
      "default": 165,
      "unit": "$/yd³",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "yards",
      "label": "Concrete needed (yd³)",
      "format": "decimal",
      "hint": null,
      "primary": true
    },
    {
      "id": "cost",
      "label": "Estimated cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "cuft",
      "label": "Raw volume (cu ft)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "bags80",
      "label": "80 lb bags",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Footing type: Continuous strip footing",
      "Trench length: 60 ft",
      "Trench width: 16 in",
      "Depth: 12 in",
      "Pier diameter: 12 in",
      "Number of piers: 8",
      "Ready-mix price: 165 $/yd³"
    ],
    "outputs": [
      "Concrete needed (yd³): 3.26",
      "Estimated cost: $537.78",
      "Raw volume (cu ft): 80",
      "80 lb bags: 147"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter footing type.",
      "Enter trench length (ft).",
      "Enter trench width (in).",
      "Enter depth (in).",
      "Enter pier diameter (in).",
      "Enter number of piers.",
      "Enter ready-mix price ($/yd³).",
      "Read your concrete needed (yd³) 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": {
        "type": "strip",
        "length": 36,
        "width": 10,
        "depth": 7,
        "diameter": 7,
        "count": 5,
        "price": 100
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "type": "strip",
        "length": 60,
        "width": 16,
        "depth": 12,
        "diameter": 12,
        "count": 8,
        "price": 165
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "type": "strip",
        "length": 96,
        "width": 26,
        "depth": 19,
        "diameter": 19,
        "count": 13,
        "price": 265
      }
    }
  ],
  "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 concrete footing calculator work?",
      "a": "Footings carry the structure, so they get poured to code depth below the frost line. Enter the trench dimensions or the pier diameter and count to get your order volume. The underlying maths is: Strip: Length × Width × Depth ÷ 27. Piers: π × r² × Depth × Count ÷ 27."
    },
    {
      "q": "What do I need to enter?",
      "a": "7 values: footing type, trench length, trench width, depth, pier diameter, number of piers, and ready-mix price. 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 concrete needed (yd³) 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/concrete-slab",
    "https://www.revenuelab.fyi/toolbox/rebar"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Concrete Footing Calculator (https://www.revenuelab.fyi/toolbox/concrete-footing)"
}