{
  "id": "cubic-inches-to-gallons",
  "version": "b738ee5b9568",
  "status": "published",
  "name": "Cubic Inches to Gallons Converter",
  "question": "Cubic inches to gallons converter",
  "summary": "Converts cubic inches (in³) to gallons (gal) and back, with the exact unit definitions.",
  "category": "convert",
  "subcategory": "volume",
  "url": "https://www.acalculator.org/convert/cubic-inches-to-gallons",
  "markdown": "https://www.acalculator.org/convert/cubic-inches-to-gallons.md",
  "kind": "formulas",
  "method": "gal = in³ × 0.004329004329 (the same as in³ ÷ 231)",
  "assumptions": [
    "1 cubic inch = 0.004329004329 gallons, from the exact definitions in NIST SP 811.",
    "Cups, ounces, tablespoons, teaspoons, pints, quarts, and gallons are US customary units: 1 US cup is 8 US fluid ounces.",
    "Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up; an answer of 1 billion or more shows at most 15 significant digits."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "value": {
        "title": "Cubic inches (in³)",
        "description": "The amount in cubic inches to convert.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "result": {
        "title": "Gallons (gal)",
        "description": "The same amount in gallons.",
        "type": "number",
        "minimum": 0,
        "maximum": 4329004329.004329
      }
    }
  },
  "solve": {
    "fillAny": 1,
    "variables": [
      "value",
      "result"
    ],
    "inputsOnly": []
  },
  "outputs": {
    "value": {
      "label": "Cubic inches (in³)",
      "description": "The amount in cubic inches to convert.",
      "format": "number"
    },
    "result": {
      "label": "Gallons (gal)",
      "description": "The amount in gallons.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "value": 1
    },
    "outputs": {
      "result": 0.004329004329004329
    },
    "text": "1 in³ = 0.004329 gal."
  },
  "examples": [
    {
      "given": {
        "value": 1
      },
      "expect": {
        "result": 0.004329004329004329
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "value": 231
      },
      "expect": {
        "result": 1
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "result": 1
      },
      "expect": {
        "value": 231
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    }
  ],
  "sources": [
    "NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8: Factors for Units Listed Alphabetically (bold factors are exact), retrieved 2026-10-19. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "NIST SP 811 (2008), footnote 13 to Appendix B: 1 in³ = 1.6387064 × 10⁻⁵ m³ exactly, retrieved 2026-10-19. https://www.nist.gov/pml/special-publication-811/nist-guide-si-footnotes",
    "NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement: 1 US gallon = 231 cubic inches, retrieved 2026-10-19. https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
  ],
  "related": [
    "cups-to-gallons",
    "gallons-to-cups",
    "gallons-to-kg",
    "gallons-to-lbs",
    "kg-to-gallons"
  ],
  "changelog": []
}