{
  "id": "surfboard-volume",
  "version": "de770c62e44b",
  "status": "published",
  "name": "Surfboard Volume Calculator",
  "question": "What surfboard volume do I need?",
  "summary": "Suggests a surfboard volume in liters from your weight and surfing level with the Guild Factor (weight in kg × factor), as a range and a middle value, or from a factor you choose.",
  "category": "sports",
  "subcategory": "fitness",
  "url": "https://www.acalculator.org/sports/surfboard-volume-calculator",
  "markdown": "https://www.acalculator.org/sports/surfboard-volume-calculator.md",
  "kind": "function",
  "method": "Board volume (liters) = weight (kg) × Guild Factor; the range uses the low and high factors of your level.",
  "assumptions": [
    "One liter of board volume per kilogram is the Guild Factor’s unit: the factor is liters ÷ kilograms.",
    "The headline uses the middle of your level’s range.",
    "Typed values are read as the exact decimals typed, so a volume exactly half a tenth rounds up."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "w": {
        "title": "Your weight",
        "description": "Your body weight, in your wetsuit if you surf in a thick one.",
        "type": [
          "number",
          "string"
        ],
        "x-quantity": "mass",
        "exclusiveMinimum": 0,
        "maximum": 500
      },
      "lvl": {
        "title": "Your level",
        "description": "Your surfing level and fitness, which sets the Guild Factor range.",
        "type": "string",
        "enum": [
          "advanced",
          "typical",
          "weekend",
          "novice",
          "custom"
        ]
      },
      "gf": {
        "title": "Guild Factor",
        "description": "Board liters per kilogram of body weight, such as 0.4.",
        "type": "number",
        "minimum": 0.1,
        "maximum": 2
      }
    }
  },
  "outputs": {
    "volume": {
      "label": "Board volume (liters)",
      "description": "Weight in kg × the middle of the Guild Factor range.",
      "format": "number"
    },
    "low": {
      "label": "Low end (liters)",
      "description": "Weight in kg × the low end of the range: for warm water and good waves.",
      "format": "number"
    },
    "high": {
      "label": "High end (liters)",
      "description": "Weight in kg × the high end of the range: for poor waves or a thick wetsuit.",
      "format": "number"
    },
    "kg": {
      "label": "Weight in kg",
      "description": "Your weight in kilograms.",
      "format": "number"
    },
    "range": {
      "label": "Guild Factor",
      "description": "The Guild Factor used, or its range.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "w": "170 lb",
      "lvl": "typical",
      "gf": 0.4
    },
    "outputs": {
      "volume": 28.530960073,
      "low": 27.759853044,
      "high": 29.302067102,
      "kg": 77.1107029,
      "range": "0.36 to 0.38 (middle 0.37)"
    },
    "text": "At 170 lb and a Guild Factor of 0.36 to 0.38 (middle 0.37), your surfboard volume is about 28.5 liters."
  },
  "examples": [
    {
      "given": {
        "w": 92.98643585,
        "lvl": "weekend"
      },
      "expect": {
        "high": 39.054303057,
        "low": 35.334845623,
        "volume": 37.19457434
      },
      "source": "Lost Surfboards by Mayhem, What’s Your Guild Factor? Surfboard Volumes Explained (Guild Factor = volume in liters ÷ body weight in kg; 0.34–0.36 advanced and very fit, 0.36–0.38 typical fitness and average to above-average skill, 0.38–0.42 lower fitness and weekend surfers, 0.40–0.50 novices or extreme conditions; © Whitney Guild 2013), https://lostsurfboards.net/whats-your-guild-factor-surfboard-volumes-explained/ (retrieved 2026-10-02) (Matt Biolos: 205 lbs, 39 liters, GF .42); hand calculation in content.mdx: 205 lb = 92.986 kg; × 0.42 = 39.05 L"
    },
    {
      "given": {
        "w": 70,
        "lvl": "advanced"
      },
      "expect": {
        "low": 23.8,
        "high": 25.2,
        "volume": 24.5,
        "range": "0.34 to 0.36 (middle 0.35)"
      },
      "source": "Lost Surfboards by Mayhem, What’s Your Guild Factor? Surfboard Volumes Explained (Guild Factor = volume in liters ÷ body weight in kg; 0.34–0.36 advanced and very fit, 0.36–0.38 typical fitness and average to above-average skill, 0.38–0.42 lower fitness and weekend surfers, 0.40–0.50 novices or extreme conditions; © Whitney Guild 2013), https://lostsurfboards.net/whats-your-guild-factor-surfboard-volumes-explained/ (retrieved 2026-10-02); hand calculation in content.mdx: 70 × 0.34 = 23.8, 70 × 0.36 = 25.2, 70 × 0.35 = 24.5 liters"
    },
    {
      "given": {
        "w": 81.6466266,
        "lvl": "custom",
        "gf": 0.45
      },
      "expect": {
        "volume": 36.74098197,
        "low": 36.74098197,
        "range": "0.45"
      },
      "source": "Lost Surfboards by Mayhem, What’s Your Guild Factor? Surfboard Volumes Explained (Guild Factor = volume in liters ÷ body weight in kg; 0.34–0.36 advanced and very fit, 0.36–0.38 typical fitness and average to above-average skill, 0.38–0.42 lower fitness and weekend surfers, 0.40–0.50 novices or extreme conditions; © Whitney Guild 2013), https://lostsurfboards.net/whats-your-guild-factor-surfboard-volumes-explained/ (retrieved 2026-10-02); hand calculation in content.mdx: 180 lb = 81.647 kg; × 0.45 = 36.74 liters"
    }
  ],
  "sources": [
    "Lost Surfboards by Mayhem, What’s Your Guild Factor? Surfboard Volumes Explained (GF measures the ratio between body weight and volume in liters; 0.34–0.36 advanced, extremely fit; 0.36–0.38 typical fitness, average to above-average skills; 0.38–0.42 lower fitness, weekend warriors; 0.40–0.50 novices or extreme conditions; low end for warm water and good waves, high end for poor conditions or thick wetsuits; example: Matt Biolos, 205 lbs, 39 liters, GF .42; © Whitney Guild 2013). https://lostsurfboards.net/whats-your-guild-factor-surfboard-volumes-explained/ (retrieved 2026-10-02)"
  ],
  "related": [
    "ski-size",
    "snowboard-size"
  ],
  "changelog": []
}