{
  "id": "amu-to-kg",
  "version": "fc3abbeea28e",
  "status": "published",
  "name": "AMU to Kg Converter",
  "question": "How do I convert amu to kg?",
  "summary": "Converts atomic mass units (u) to kilograms (kg) and back, with the CODATA 2022 atomic mass unit.",
  "category": "convert",
  "subcategory": "weight",
  "url": "https://www.acalculator.org/convert/amu-to-kg",
  "markdown": "https://www.acalculator.org/convert/amu-to-kg.md",
  "kind": "formulas",
  "method": "kg = u × 1.66053906892 × 10⁻²⁷",
  "assumptions": [
    "1 u (unified atomic mass unit, or dalton) = 1.66053906892 × 10⁻²⁷ kg, the CODATA 2022 recommended value (NIST); it is measured, with a standard uncertainty of 0.00000000052 × 10⁻²⁷ kg (3.1 parts in 10¹⁰). The page converts with this value as if exact.",
    "Exact on the typed decimals: the answer shows 6 significant digits as d.ddddd × 10ⁿ (trailing zeros dropped), rounded half up; 0 shows as 0. A value above 0 whose answer is below 10⁻³⁰⁰ gives no answer."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "value": {
        "title": "Atomic mass units (u)",
        "description": "The amount in atomic mass units to convert.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "result": {
        "title": "Kilograms (kg)",
        "description": "The same amount in kilograms.",
        "type": "number",
        "minimum": 0,
        "maximum": 1.66053906892e-15
      }
    }
  },
  "solve": {
    "fillAny": 1,
    "variables": [
      "value",
      "result"
    ],
    "inputsOnly": []
  },
  "outputs": {
    "value": {
      "label": "Atomic mass units (u)",
      "description": "The amount in atomic mass units to convert.",
      "format": "number"
    },
    "result": {
      "label": "Kilograms (kg)",
      "description": "The amount in kilograms.",
      "format": "number"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "value": 1
    },
    "outputs": {
      "result": 1.66053906892e-27
    },
    "text": "1 u = 1.66054 × 10⁻²⁷ kg."
  },
  "examples": [
    {
      "given": {
        "value": 1
      },
      "expect": {
        "result": 1.66053906892e-27
      },
      "source": "NIST CODATA 2022 value of the atomic mass unit (https://physics.nist.gov/cgi-bin/cuu/Value?ukg)"
    },
    {
      "given": {
        "value": 12
      },
      "expect": {
        "result": 1.992646882704e-26
      },
      "source": "NIST CODATA 2022 value of the atomic mass unit (https://physics.nist.gov/cgi-bin/cuu/Value?ukg)"
    }
  ],
  "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 2026-10-18. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8",
    "NIST, CODATA Internationally Recommended 2022 Values of the Fundamental Physical Constants: unified atomic mass unit, 1.660 539 068 92(52) × 10⁻²⁷ kg, relative standard uncertainty 3.1 × 10⁻¹⁰, retrieved 2026-10-19. https://physics.nist.gov/cgi-bin/cuu/Value?ukg"
  ],
  "related": [
    "kg-to-lbs",
    "lbs-to-kg",
    "grams-to-kg",
    "kg-to-grams",
    "kg-to-oz"
  ],
  "changelog": []
}