{
  "slug": "4x8-shed-pad-concrete-calculator",
  "title": "4x8 Shed Pad Concrete Calculator",
  "heading": "4x8 Shed Pad Concrete Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/4x8-shed-pad-concrete-calculator",
  "summary": "Concrete needed for a small 4x8 shed or generator pad, bag count included.",
  "description": "A 4x8 pad is a common size for a small storage shed, generator, or AC condenser base. This calculator defaults to 4 inches thick, small enough that most people mix it themselves with 80-lb bags rather than ordering ready-mix, so both the bag count and the ready-mix cubic yardage are shown side by side along with total material cost.",
  "formula": "Cubic Yards = (Length × Width × Thickness in inches ÷ 12) ÷ 27 × (1 + Waste%). Bags (80lb) ≈ Cubic Yards × 45.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=4x8-shed-pad-concrete-calculator",
  "inputs": [
    {
      "id": "length",
      "label": "Pad length",
      "kind": "number",
      "hint": null,
      "default": 8,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "width",
      "label": "Pad width",
      "kind": "number",
      "hint": null,
      "default": 4,
      "unit": "ft",
      "min": 1,
      "max": null
    },
    {
      "id": "thickness",
      "label": "Thickness",
      "kind": "number",
      "hint": null,
      "default": 4,
      "unit": "in",
      "min": 2,
      "max": 12
    },
    {
      "id": "waste",
      "label": "Waste factor",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 30
    },
    {
      "id": "bagPrice",
      "label": "Price per 80-lb bag",
      "kind": "number",
      "hint": null,
      "default": 6.5,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "bags",
      "label": "80-lb bags needed",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "cubicYards",
      "label": "Equivalent ready-mix yards",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "cost",
      "label": "Estimated bag cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "cubicFeet",
      "label": "Total cubic feet",
      "format": "decimal",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Pad length: 8 ft",
      "Pad width: 4 ft",
      "Thickness: 4 in",
      "Waste factor: 10 %",
      "Price per 80-lb bag: 6.5 $"
    ],
    "outputs": [
      "80-lb bags needed: 20",
      "Equivalent ready-mix yards: 0.43",
      "Estimated bag cost: $130",
      "Total cubic feet: 10.7"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter pad length (ft).",
      "Enter pad width (ft).",
      "Enter thickness (in).",
      "Enter waste factor (%).",
      "Enter price per 80-lb bag ($).",
      "Read your 80-lb bags 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": 5,
        "width": 2,
        "thickness": 2.4,
        "waste": 6,
        "bagPrice": 3.9
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "length": 8,
        "width": 4,
        "thickness": 4,
        "waste": 10,
        "bagPrice": 6.5
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "length": 13,
        "width": 6,
        "thickness": 6.4,
        "waste": 16,
        "bagPrice": 10.4
      }
    }
  ],
  "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 many bags of concrete for a 4x8 shed pad?",
      "a": "At 4 inches thick with 10% waste, about 20 bags of 80-lb concrete mix — well within DIY mixing range for a weekend project."
    },
    {
      "q": "Do I need gravel under a 4x8 shed pad?",
      "a": "Yes, 3-4 inches of compacted gravel base is standard under any shed slab to improve drainage and reduce frost heave, in addition to the concrete volume calculated here."
    },
    {
      "q": "Is a slab necessary for a small shed, or can I use pavers?",
      "a": "A poured pad gives the most stable, level, rot-resistant base, but a well-compacted paver or gravel pad works fine for lightweight sheds under 100 square feet in areas without heavy frost."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/10x12-shed-calculator",
    "https://www.revenuelab.fyi/toolbox/8x10-shed-floor-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — 4x8 Shed Pad Concrete Calculator (https://www.revenuelab.fyi/toolbox/4x8-shed-pad-concrete-calculator)"
}