{
  "id": "decimal-to-inches",
  "version": "5a01c59c035d",
  "status": "published",
  "name": "Decimal to Inches Calculator",
  "question": "How do I convert decimal to inches?",
  "summary": "Converts decimal inches or decimal feet to inches and fractions of an inch, to the nearest 1/16 or any mark from 1/2 to 1/64, with feet and inches.",
  "category": "convert",
  "subcategory": "length",
  "url": "https://www.acalculator.org/convert/decimal-to-inches",
  "markdown": "https://www.acalculator.org/convert/decimal-to-inches.md",
  "kind": "function",
  "method": "Inches = the decimal (× 12 when it is in feet). Rounded inches = round(inches × D) ÷ D for the mark 1/D, halves rounded up, written as a whole number and a fraction in lowest terms.",
  "assumptions": [
    "The decimal is taken exactly as typed; 1 ft = 12 in and 1 in = 25.4 mm exactly.",
    "A length exactly halfway between two marks rounds up to the larger mark."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "d": {
        "title": "Decimal",
        "description": "The decimal length, for example 5.19.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000
      },
      "u": {
        "title": "The decimal is in",
        "description": "Inches (5.19 in) or feet (5.75 ft).",
        "type": "string",
        "enum": [
          "in",
          "ft"
        ]
      },
      "n": {
        "title": "Nearest",
        "description": "The smallest mark to round to: 1/16 inch on most tape measures.",
        "type": "string",
        "enum": [
          "2",
          "4",
          "8",
          "16",
          "32",
          "64"
        ]
      }
    }
  },
  "outputs": {
    "inches": {
      "label": "Inches",
      "description": "The length in whole inches and a fraction, rounded to the nearest mark.",
      "format": "text"
    },
    "feetInches": {
      "label": "Feet and inches",
      "description": "The rounded length as whole feet and inches.",
      "format": "text"
    },
    "exact": {
      "label": "Exact inches (decimal)",
      "description": "The length in inches before rounding.",
      "format": "number"
    },
    "error": {
      "label": "Rounding error (in)",
      "description": "The rounded length minus the exact length, in inches.",
      "format": "number"
    },
    "mm": {
      "label": "Millimeters",
      "description": "The exact length in millimeters (1 in = 25.4 mm).",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "d": 5.19,
      "u": "in",
      "n": "16"
    },
    "outputs": {
      "inches": "5 3/16 in",
      "feetInches": "0 ft 5 3/16 in",
      "exact": 5.19,
      "error": -0.0025,
      "mm": 131.826
    },
    "text": "5.19 inches is about 5 3/16 in."
  },
  "examples": [
    {
      "given": {
        "d": 5.19,
        "u": "in",
        "n": "16"
      },
      "expect": {
        "inches": "5 3/16 in",
        "feetInches": "0 ft 5 3/16 in",
        "error": -0.0025
      },
      "source": "OpenStax, Prealgebra 2e, §5.1 Decimals (a decimal as a fraction, rounding), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-10-05); hand calculation in content.mdx: 83/16 = 5 3/16"
    },
    {
      "given": {
        "d": 5.75,
        "u": "ft",
        "n": "16"
      },
      "expect": {
        "inches": "69 in",
        "feetInches": "5 ft 9 in",
        "exact": 69,
        "mm": 1752.6
      },
      "source": "NIST SP 811, Appendix B.8 (1 ft = 12 in = 0.3048 m; 1 in = 2.54 cm), https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8 (retrieved 2026-10-05); hand calculation in content.mdx: 5.75 × 12 = 69"
    },
    {
      "given": {
        "d": 0.3125,
        "u": "in",
        "n": "8"
      },
      "expect": {
        "inches": "3/8 in",
        "error": 0.0625
      },
      "source": "OpenStax, Prealgebra 2e, §5.1 Decimals (a decimal as a fraction, rounding), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-10-05); hand calculation in content.mdx: 0.3125 = 5/16, halfway between 2/8 and 3/8"
    },
    {
      "given": {
        "d": 2.4,
        "u": "ft",
        "n": "32"
      },
      "expect": {
        "inches": "28 13/16 in",
        "feetInches": "2 ft 4 13/16 in",
        "exact": 28.8,
        "error": 0.0125
      },
      "source": "NIST SP 811, Appendix B.8 (1 ft = 12 in = 0.3048 m; 1 in = 2.54 cm), https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8 (retrieved 2026-10-05); hand calculation in content.mdx: 2.4 × 12 = 28.8; 28.8 × 32 = 921.6 → 922/32 = 28 13/16"
    }
  ],
  "sources": [
    "OpenStax, Prealgebra 2e, §5.1 Decimals: a decimal as a fraction and rounding to a place. CC BY 4.0. Retrieved 2026-10-05. https://openstax.org/books/prealgebra-2e/pages/5-1-decimals",
    "NIST Special Publication 811, Appendix B.8: 1 ft = 0.3048 m and 1 in = 2.54 cm exactly, so 1 ft = 12 in. Retrieved 2026-10-05. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8"
  ],
  "related": [
    "decimal-to-fraction",
    "fraction-to-decimal"
  ],
  "changelog": []
}