{
  "id": "abv",
  "version": "b418022f0425",
  "status": "published",
  "name": "ABV Calculator",
  "question": "What is my brew’s ABV?",
  "summary": "Computes the alcohol by volume of beer, wine, cider or mead from the original and final specific gravity, by the standard formula or the alternate formula for strong brews, with alcohol by weight and apparent attenuation.",
  "category": "food",
  "url": "https://www.acalculator.org/food/abv-calculator",
  "markdown": "https://www.acalculator.org/food/abv-calculator.md",
  "kind": "function",
  "method": "standard: ABV = (OG − FG) × 131.25; alternate: ABV = 76.08 × (OG − FG) ÷ (1.775 − OG) × FG ÷ 0.794; ABW = ABV × 0.794 ÷ FG",
  "assumptions": [
    "Gravities are specific gravities measured at the hydrometer’s calibration temperature, or corrected to it.",
    "Apparent attenuation uses the measured final gravity, which alcohol lowers, so it can pass 100% in a dry wine or cider.",
    "Sugar added after the original reading (priming or feeding) is not counted."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "og": {
        "title": "Original gravity (OG)",
        "description": "The specific gravity before fermentation, such as 1.050.",
        "type": "number",
        "minimum": 1.001,
        "maximum": 1.2
      },
      "fg": {
        "title": "Final gravity (FG)",
        "description": "The specific gravity after fermentation, such as 1.010.",
        "type": "number",
        "minimum": 0.98,
        "maximum": 1.2
      },
      "formula": {
        "title": "Formula",
        "description": "The standard formula, or the alternate formula that is closer for strong brews.",
        "type": "string",
        "enum": [
          "standard",
          "alternate"
        ]
      }
    }
  },
  "outputs": {
    "abv": {
      "label": "Alcohol by volume",
      "description": "The alcohol as a percent of the volume.",
      "format": "percent"
    },
    "abw": {
      "label": "Alcohol by weight",
      "description": "The alcohol as a percent of the weight: ABV × 0.794 ÷ FG.",
      "format": "percent"
    },
    "attenuation": {
      "label": "Apparent attenuation",
      "description": "How much of the gravity above water fermented away: (OG − FG) ÷ (OG − 1).",
      "format": "percent"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "og": 1.05,
      "fg": 1.01,
      "formula": "standard"
    },
    "outputs": {
      "abv": 5.250000000000004,
      "abw": 4.127227722772281,
      "attenuation": 80
    },
    "text": "From 1.05 down to 1.01, the ABV is 5.25%."
  },
  "examples": [
    {
      "given": {
        "og": 1.05,
        "fg": 1.01,
        "formula": "standard"
      },
      "expect": {
        "abv": 5.25,
        "attenuation": 80
      },
      "source": "hand calculation in content.mdx: (1.050 − 1.010) × 131.25 = 5.25%; 0.040 ÷ 0.050 = 80%"
    },
    {
      "given": {
        "og": 1.05,
        "fg": 1.01,
        "formula": "alternate"
      },
      "expect": {
        "abv": 5.339411100495092,
        "abw": 4.197517241379311
      },
      "source": "Hall, Brew by the Numbers, Zymurgy 18(2), 1995, as cited in content.mdx; hand calculation in content.mdx: 76.08 × 0.040 ÷ 0.725 = 4.198% ABW; × 1.010 ÷ 0.794 = 5.34% ABV"
    },
    {
      "given": {
        "og": 1.1,
        "fg": 1.02,
        "formula": "alternate"
      },
      "expect": {
        "abv": 11.583408900083963
      },
      "source": "hand calculation in content.mdx: 76.08 × 0.080 ÷ 0.675 = 9.017; × 1.020 ÷ 0.794 = 11.58% (standard: 10.50%)"
    },
    {
      "given": {
        "og": 1.09,
        "fg": 0.995,
        "formula": "standard"
      },
      "expect": {
        "abv": 12.46875,
        "attenuation": 105.55555555555556
      },
      "source": "hand calculation in content.mdx: 0.095 × 131.25 = 12.47%; 0.095 ÷ 0.090 = 105.6%"
    }
  ],
  "sources": [
    "Hall, M. L. (1995). Brew by the Numbers: Add Up What’s in Your Beer. Zymurgy, 18(2). Alternate formula ABV = 76.08 (OG − FG) ÷ (1.775 − OG) × FG ÷ 0.794.",
    "Brewday documentation, brew.utilities.abv: standard ABV = (OG − FG) × 131.25 and the alternate formula with its sources. https://brewday.readthedocs.io/en/latest/api/utilities/abv.html"
  ],
  "related": [],
  "changelog": []
}