{
  "source": "Pour Calculator deterministic concrete engine",
  "generatedAt": "2026-09-18",
  "title": "Post Hole Concrete Bag Chart",
  "units": "US customary",
  "assumptions": {
    "defaultWastePercent": 10,
    "geometry": "Each hole is treated as a full concrete cylinder.",
    "excluded": "Post displacement, gravel base, bell footings, flared bases and soil overdig are not subtracted or added.",
    "rounding": "Bag counts are rounded up to whole bags after adding waste.",
    "caution": "Confirm footing size, frost depth, utilities and local code before digging or pouring."
  },
  "formula": "volume cubic feet = pi * (diameter inches / 24)^2 * depth feet",
  "rows": [
    {
      "useLines": [
        "Small fence",
        "line post"
      ],
      "diameterInches": 8,
      "depthInches": 24,
      "use": "Small fence line post",
      "holeSize": "8 in dia x 24 in deep",
      "baseCubicFeet": 0.6981317007977317,
      "withTenPercentWasteCubicFeet": 0.767944870877505,
      "bagCounts": {
        "50": 3,
        "60": 2,
        "80": 2
      }
    },
    {
      "useLines": [
        "Line post",
        "compact hole"
      ],
      "diameterInches": 10,
      "depthInches": 24,
      "use": "Line post compact hole",
      "holeSize": "10 in dia x 24 in deep",
      "baseCubicFeet": 1.090830782496456,
      "withTenPercentWasteCubicFeet": 1.1999138607461017,
      "bagCounts": {
        "50": 4,
        "60": 3,
        "80": 2
      }
    },
    {
      "useLines": [
        "Line post",
        "deeper set"
      ],
      "diameterInches": 10,
      "depthInches": 30,
      "use": "Line post deeper set",
      "holeSize": "10 in dia x 30 in deep",
      "baseCubicFeet": 1.36353847812057,
      "withTenPercentWasteCubicFeet": 1.4998923259326271,
      "bagCounts": {
        "50": 4,
        "60": 4,
        "80": 3
      }
    },
    {
      "useLines": [
        "4x4 line post",
        "30 in depth"
      ],
      "diameterInches": 12,
      "depthInches": 30,
      "use": "4x4 line post 30 in depth",
      "holeSize": "12 in dia x 30 in deep",
      "baseCubicFeet": 1.9634954084936207,
      "withTenPercentWasteCubicFeet": 2.159844949342983,
      "bagCounts": {
        "50": 6,
        "60": 5,
        "80": 4
      }
    },
    {
      "useLines": [
        "4x4/gate",
        "36 in depth"
      ],
      "diameterInches": 12,
      "depthInches": 36,
      "use": "4x4/gate 36 in depth",
      "holeSize": "12 in dia x 36 in deep",
      "baseCubicFeet": 2.356194490192345,
      "withTenPercentWasteCubicFeet": 2.5918139392115793,
      "bagCounts": {
        "50": 7,
        "60": 6,
        "80": 5
      }
    },
    {
      "useLines": [
        "Deck tube",
        "48 in depth"
      ],
      "diameterInches": 12,
      "depthInches": 48,
      "use": "Deck tube 48 in depth",
      "holeSize": "12 in dia x 48 in deep",
      "baseCubicFeet": 3.141592653589793,
      "withTenPercentWasteCubicFeet": 3.455751918948773,
      "bagCounts": {
        "50": 10,
        "60": 8,
        "80": 6
      }
    },
    {
      "useLines": [
        "Large deck",
        "pier"
      ],
      "diameterInches": 16,
      "depthInches": 36,
      "use": "Large deck pier",
      "holeSize": "16 in dia x 36 in deep",
      "baseCubicFeet": 4.18879020478639,
      "withTenPercentWasteCubicFeet": 4.607669225265029,
      "bagCounts": {
        "50": 13,
        "60": 11,
        "80": 8
      }
    },
    {
      "useLines": [
        "Large footing",
        "18 in tube"
      ],
      "diameterInches": 18,
      "depthInches": 48,
      "use": "Large footing 18 in tube",
      "holeSize": "18 in dia x 48 in deep",
      "baseCubicFeet": 7.0685834705770345,
      "withTenPercentWasteCubicFeet": 7.775441817634738,
      "bagCounts": {
        "50": 21,
        "60": 18,
        "80": 13
      }
    }
  ],
  "sources": [
    {
      "label": "QUIKRETE quantity calculator",
      "url": "https://www.quikrete.com/calculator/main.asp"
    },
    {
      "label": "Sakrete concrete calculators",
      "url": "https://www.sakrete.com/concrete-calculators/"
    },
    {
      "label": "Sakrete Fast-Setting Concrete Mix",
      "url": "https://www.sakrete.com/product/fast-setting-concrete-mix/"
    }
  ]
}