{
  "slug": "concrete-slab-12x12-calculator",
  "title": "12x12 Concrete Slab Calculator",
  "heading": "12x12 Concrete Slab Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/concrete-slab-12x12-calculator",
  "summary": "Yardage and bag counts for a 144 sq ft slab — a common patio, carport, or workshop pad size.",
  "description": "12x12 is a popular slab footprint for detached workshops, carports, and larger patios, landing at 144 square feet — 44% more area than a 10x10 pad, so the concrete volume scales accordingly. This calculator fixes the footprint at 12 feet by 12 feet and lets you dial in thickness and waste factor, since a 12x12 pad meant to carry a car or workshop equipment often gets poured at 5-6 inches with reinforcement rather than the 4-inch standard used for a simple patio. It returns both the ready-mix cubic yards to order from a batch plant and the 80lb bag equivalent for anyone hand-mixing a job this size, though at 144 square feet and 4+ inches thick, hand-mixing 90+ bags is a serious labor undertaking most people outsource to a delivered truck instead. The tool also shows raw cubic feet so you can cross-check your own measurements if your actual pad isn't a perfect 12x12 square.",
  "formula": "Volume = 144 sq ft × Thickness(ft) ÷ 27, × (1 + Waste%). Bags = (144 × Thickness(ft) ÷ 0.6) × (1 + Waste%).",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=concrete-slab-12x12-calculator",
  "inputs": [
    {
      "id": "thicknessIn",
      "label": "Slab thickness",
      "kind": "number",
      "hint": null,
      "default": 4,
      "unit": "in",
      "min": 3,
      "max": 8
    },
    {
      "id": "wastePct",
      "label": "Waste factor",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 25
    }
  ],
  "outputs": [
    {
      "id": "cubicYards",
      "label": "Ready-mix needed",
      "format": "decimal",
      "hint": "cu yd",
      "primary": true
    },
    {
      "id": "bags80",
      "label": "Equivalent 80lb bags",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "cubicFeet",
      "label": "Total cubic feet",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "area",
      "label": "Slab area",
      "format": "number",
      "hint": "sq ft",
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Slab thickness: 4 in",
      "Waste factor: 10 %"
    ],
    "outputs": [
      "Ready-mix needed: 1.96",
      "Equivalent 80lb bags: 88",
      "Total cubic feet: 48",
      "Slab area: 144"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter slab thickness (in).",
      "Enter waste factor (%).",
      "Read your ready-mix 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": {
        "thicknessIn": 3,
        "wastePct": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "thicknessIn": 4,
        "wastePct": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "thicknessIn": 6.4,
        "wastePct": 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": "How much concrete for a 12x12 slab at 4 inches?",
      "a": "About 1.78 cubic yards raw, or roughly 1.95-2.0 cubic yards with a standard 10% waste factor — most suppliers will round this to a 2 cubic yard order."
    },
    {
      "q": "Is a 12x12 pad big enough for a workshop?",
      "a": "Yes, 144 square feet comfortably fits a single-car workshop or large storage building; if you plan to drive a vehicle onto it, budget for 5-6 inch thickness with wire mesh rather than the 4-inch patio standard."
    },
    {
      "q": "How many bags of concrete for a 12x12 slab?",
      "a": "At 4 inches thick with 10% waste, roughly 105-110 bags of 80lb mix — a volume most contractors would rather order as delivered ready-mix instead of hand-mixing."
    },
    {
      "q": "Does a 12x12 slab need a control joint?",
      "a": "Yes, a slab this size should have at least one control joint (often a center cross-cut) to control where cracking occurs as the concrete shrinks during curing."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/concrete-slab-10x10-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 — 12x12 Concrete Slab Calculator (https://www.revenuelab.fyi/toolbox/concrete-slab-12x12-calculator)"
}