{
  "id": "pool-pump",
  "version": "c841be7d8853",
  "status": "published",
  "name": "Pool Pump Calculator",
  "question": "What pool pump flow do I need?",
  "summary": "Works out the pump flow rate a pool needs to turn its whole volume over in a chosen time, in gallons per minute, liters per minute and cubic meters per hour, from the volume or the pool’s size.",
  "category": "construction",
  "subcategory": "pools",
  "url": "https://www.acalculator.org/construction/pool-pump-calculator",
  "markdown": "https://www.acalculator.org/construction/pool-pump-calculator.md",
  "kind": "function",
  "method": "flow = pool volume ÷ turnover time. Rectangle volume = length × width × average depth; round = π × (diameter ÷ 2)² × depth.",
  "assumptions": [
    "The flow is the rate that moves the whole pool volume once in the turnover time; the pump must deliver it against the head loss of your pipes and filter.",
    "Your local health code sets the turnover time for a public pool; for a home pool, choose a time to suit how the pool is used.",
    "1 US gallon = 231 cubic inches = 3.785411784 L; 1 ft = 0.3048 m."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "by": {
        "title": "I know",
        "description": "The pool volume, or the pool’s size to work the volume out from.",
        "type": "string",
        "enum": [
          "volume",
          "size"
        ]
      },
      "v": {
        "title": "Pool volume",
        "description": "How much water the pool holds.",
        "type": "number",
        "minimum": 1,
        "maximum": 100000000
      },
      "vu": {
        "title": "Volume unit",
        "description": "US gallons, liters or cubic meters.",
        "type": "string",
        "enum": [
          "gal",
          "L",
          "m3"
        ]
      },
      "shape": {
        "title": "Shape",
        "description": "A rectangular pool, or a round one.",
        "type": "string",
        "enum": [
          "rect",
          "round"
        ]
      },
      "lu": {
        "title": "Size in",
        "description": "Feet or meters for the pool size.",
        "type": "string",
        "enum": [
          "ft",
          "m"
        ]
      },
      "l": {
        "title": "Length",
        "description": "The length of a rectangular pool.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 1000
      },
      "w": {
        "title": "Width",
        "description": "The width of a rectangular pool.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 1000
      },
      "dia": {
        "title": "Diameter",
        "description": "The inside diameter of a round pool.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 1000
      },
      "d": {
        "title": "Average depth",
        "description": "The average water depth: (shallow end + deep end) ÷ 2 for a sloped floor.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 1000
      },
      "h": {
        "title": "Turnover time (hours)",
        "description": "The time the pump should take to move the whole pool volume through the filter once.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 48
      }
    }
  },
  "outputs": {
    "gpm": {
      "label": "Flow rate (gal/min)",
      "description": "Volume in US gallons ÷ minutes of turnover.",
      "format": "number"
    },
    "lpm": {
      "label": "Flow rate (L/min)",
      "description": "Volume in liters ÷ minutes of turnover.",
      "format": "number"
    },
    "m3h": {
      "label": "Flow rate (m³/h)",
      "description": "Volume in cubic meters ÷ hours of turnover.",
      "format": "number"
    },
    "gallons": {
      "label": "Pool volume (US gal)",
      "description": "The pool volume in US gallons.",
      "format": "number"
    },
    "liters": {
      "label": "Pool volume (L)",
      "description": "The pool volume in liters.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "by": "volume",
      "v": 20000,
      "vu": "gal",
      "shape": "rect",
      "lu": "ft",
      "l": 32,
      "w": 16,
      "dia": 24,
      "d": 5,
      "h": 8
    },
    "outputs": {
      "gpm": 41.666666666666664,
      "lpm": 157.725491,
      "m3h": 9.46352946,
      "gallons": 20000,
      "liters": 75708.23568
    },
    "text": "The pump needs about 41.7 gallons per minute (9.46 m³/h)."
  },
  "examples": [
    {
      "given": {
        "by": "volume",
        "v": 20000,
        "vu": "gal",
        "h": 8
      },
      "expect": {
        "gpm": 41.666666666666664,
        "lpm": 157.725491,
        "m3h": 9.46352946,
        "liters": 75708.23568
      },
      "source": "hand calculation in content.mdx: 20,000 ÷ (8 × 60) = 41.67 gal/min; Python 3: Fraction; NIST Handbook 44 (2024), Appendix C (1 gal = 231 in³), https://www.nist.gov/document/nist-hb-44-2024-appendix-c-general-tables-units-measurement; NIST SP 811, Appendix B.8 (1 in = 0.0254 m, 1 ft = 0.3048 m), https://www.nist.gov/pml/special-publication-811"
    },
    {
      "given": {
        "by": "size",
        "shape": "rect",
        "lu": "ft",
        "l": 32,
        "w": 16,
        "d": 5,
        "h": 6
      },
      "expect": {
        "gallons": 19150.12987012987,
        "gpm": 53.1948051948052
      },
      "source": "hand calculation in content.mdx: 32 × 16 × 5 = 2,560 ft³ × 1,728 ÷ 231 = 19,150.13 gal; ÷ 360 min = 53.19 gal/min; NIST Handbook 44 (2024), Appendix C (1 gal = 231 in³), https://www.nist.gov/document/nist-hb-44-2024-appendix-c-general-tables-units-measurement; NIST SP 811, Appendix B.8 (1 in = 0.0254 m, 1 ft = 0.3048 m), https://www.nist.gov/pml/special-publication-811"
    },
    {
      "given": {
        "by": "size",
        "shape": "round",
        "lu": "m",
        "dia": 5,
        "d": 1.2,
        "h": 8
      },
      "expect": {
        "m3h": 2.9452431127404313,
        "lpm": 49.08738521234052
      },
      "source": "hand calculation in content.mdx: π × 2.5² × 1.2 = 23.562 m³; ÷ 8 h = 2.945 m³/h; Python 3: math.pi",
      "tolerance": 1e-12
    },
    {
      "given": {
        "by": "volume",
        "v": 50,
        "vu": "m3",
        "h": 0.5
      },
      "expect": {
        "m3h": 100,
        "lpm": 1666.6666666666667
      },
      "source": "hand calculation in content.mdx: 50 m³ ÷ 0.5 h = 100 m³/h"
    }
  ],
  "sources": [
    "CDC, Model Aquatic Health Code (turnover times for public aquatic venues). https://www.cdc.gov/model-aquatic-health-code/php/our-work/index.html (retrieved 2026-10-19)",
    "NIST Handbook 44 (2024), Appendix C, General Tables of Units of Measurement (1 US gallon = 231 cubic inches). https://www.nist.gov/document/nist-hb-44-2024-appendix-c-general-tables-units-measurement (retrieved 2026-10-19)",
    "NIST Special Publication 811 (2008), Appendix B.8: 1 in = 0.0254 m and 1 ft = 0.3048 m exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-19)"
  ],
  "related": [
    "pool-volume",
    "pool-salt"
  ],
  "changelog": []
}