{
  "id": "mm-to-inches",
  "version": "b2375577e790",
  "status": "published",
  "name": "Mm to Inches Converter",
  "question": "How do I convert mm to inches?",
  "summary": "Converts millimeters (mm) to inches (in) and back, with the exact unit definitions.",
  "category": "convert",
  "subcategory": "units",
  "url": "https://www.acalculator.org/convert/mm-to-inches",
  "markdown": "https://www.acalculator.org/convert/mm-to-inches.md",
  "kind": "formulas",
  "method": "in = mm × 0.0393700787402 (the same as mm ÷ 25.4)",
  "assumptions": [
    "1 millimeter = 0.0393700787402 inches, from the exact definitions in NIST SP 811.",
    "The answer shows at most 6 decimal places; the calculation keeps full precision."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "value": {
        "title": "Millimeters (mm)",
        "description": "The amount in millimeters to convert.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "result": {
        "title": "Inches (in)",
        "description": "The same amount in inches.",
        "type": "number",
        "minimum": 0,
        "maximum": 39370078740.15748
      }
    }
  },
  "solve": {
    "fillAny": 1,
    "variables": [
      "value",
      "result"
    ],
    "inputsOnly": []
  },
  "outputs": {
    "value": {
      "label": "Millimeters (mm)",
      "description": "The amount in millimeters to convert.",
      "format": "number"
    },
    "result": {
      "label": "Inches (in)",
      "description": "The amount in inches.",
      "format": "number"
    },
    "fraction": {
      "label": "Nearest 1/64 inch",
      "description": "The length in inches rounded to the nearest 1/64 inch, as on a tape measure.",
      "format": "fraction"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "value": 1
    },
    "outputs": {
      "result": 0.03937007874015748,
      "fraction": 0.03937007874015748
    },
    "text": "1 mm = 0.03937 in."
  },
  "examples": [
    {
      "given": {
        "value": 1
      },
      "expect": {
        "result": 0.03937007874015748
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "value": 25
      },
      "expect": {
        "result": 0.984251968503937
      },
      "source": "exact unit definitions in NIST SP 811 (2008), Appendix B.8"
    },
    {
      "given": {
        "result": 0.984251968503937
      },
      "expect": {
        "value": 25
      },
      "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. https://www.nist.gov/pml/special-publication-811"
  ],
  "related": [
    "cm-to-inches",
    "inches-to-cm",
    "inches-to-feet"
  ],
  "changelog": []
}