{
  "id": "weight-converter",
  "version": "e01fb97b18d7",
  "status": "published",
  "name": "Weight Calculator",
  "question": "How do I convert a weight?",
  "summary": "Converts a weight from any unit to any other: milligrams, grams, kilograms, tons, ounces, pounds, stone, and grains.",
  "category": "convert",
  "subcategory": "units",
  "url": "https://www.acalculator.org/convert/weight",
  "markdown": "https://www.acalculator.org/convert/weight.md",
  "kind": "function",
  "method": "converted = weight × (kilograms per \"From\" unit) ÷ (kilograms per \"To\" unit)",
  "assumptions": [
    "Kilograms per unit come from the exact definitions in NIST SP 811: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb, 1 grain = 1/7,000 lb, 1 US short ton = 2,000 lb, 1 metric ton = 1,000 kg, 1 UK long ton = 2,240 lb.",
    "1 stone = 14 lb (UK Weights and Measures Act 1985).",
    "Ounces are avoirdupois ounces, the ounces of weight. Troy ounces (for precious metals) are a different unit.",
    "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": {
      "amount": {
        "title": "Weight",
        "description": "The weight to convert, in the \"From\" unit.",
        "type": "number",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "from": {
        "title": "From",
        "description": "The unit the weight is in.",
        "type": "string",
        "enum": [
          "mg",
          "g",
          "kg",
          "t",
          "oz",
          "lb",
          "st",
          "ton",
          "lton",
          "gr",
          "ug"
        ]
      },
      "to": {
        "title": "To",
        "description": "The unit to convert the weight to.",
        "type": "string",
        "enum": [
          "mg",
          "g",
          "kg",
          "t",
          "oz",
          "lb",
          "st",
          "ton",
          "lton",
          "gr",
          "ug"
        ]
      }
    }
  },
  "outputs": {
    "result": {
      "label": "Converted weight",
      "description": "The weight in the \"To\" unit.",
      "format": "number"
    },
    "kg": {
      "label": "Kilograms (kg)",
      "description": "The weight in kilograms.",
      "format": "number"
    },
    "g": {
      "label": "Grams (g)",
      "description": "The weight in grams.",
      "format": "number"
    },
    "lb": {
      "label": "Pounds (lb)",
      "description": "The weight in pounds.",
      "format": "number"
    },
    "oz": {
      "label": "Ounces (oz)",
      "description": "The weight in avoirdupois ounces.",
      "format": "number"
    },
    "lbOz": {
      "label": "Pounds and ounces",
      "description": "Whole pounds and the ounces left over, to 0.01 oz.",
      "format": "text"
    },
    "stLb": {
      "label": "Stone and pounds",
      "description": "Whole stone and the pounds left over, to 0.01 lb.",
      "format": "text"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "from": "lb",
      "to": "kg",
      "amount": 150
    },
    "outputs": {
      "result": 68.0388555,
      "kg": 68.0388555,
      "g": 68038.85549999999,
      "lb": 149.99999999999997,
      "oz": 2399.9999999999995,
      "lbOz": "150 lb 0 oz",
      "stLb": "10 st 10 lb"
    },
    "text": "150 pounds (lb) = 68.038856 kilograms (kg)."
  },
  "examples": [
    {
      "given": {
        "amount": 150,
        "from": "lb",
        "to": "kg"
      },
      "expect": {
        "result": 68.0388555,
        "lb": 150,
        "lbOz": "150 lb 0 oz",
        "stLb": "10 st 10 lb"
      },
      "source": "NIST SP 811 (2008) B.8: 1 lb = 0.45359237 kg exactly; 150 × 0.45359237 = 68.0388555 (content.mdx)"
    },
    {
      "given": {
        "amount": 1,
        "from": "kg",
        "to": "lb"
      },
      "expect": {
        "result": 2.2046226218487757,
        "oz": 35.27396194958041,
        "lbOz": "2 lb 3.27 oz",
        "stLb": "0 st 2.2 lb"
      },
      "source": "NIST SP 811 (2008) B.8: 1 kg = 1 ÷ 0.45359237 lb; 1 oz = 1/16 lb (content.mdx)"
    },
    {
      "given": {
        "amount": 10,
        "from": "st",
        "to": "kg"
      },
      "expect": {
        "result": 63.5029318
      },
      "source": "UK Weights and Measures Act 1985, Schedule 1: 1 stone = 14 lb; 140 × 0.45359237 = 63.5029318 (content.mdx)"
    },
    {
      "given": {
        "amount": 1,
        "from": "lton",
        "to": "t"
      },
      "expect": {
        "result": 1.0160469088
      },
      "source": "NIST SP 811 (2008) B.8: 1 long ton = 2,240 lb = 1,016.0469088 kg; 1 t = 1,000 kg (content.mdx)"
    },
    {
      "given": {
        "amount": 1,
        "from": "ton",
        "to": "lb"
      },
      "expect": {
        "result": 2000
      },
      "source": "NIST SP 811 (2008) B.8: 1 short ton = 2,000 lb (content.mdx)"
    }
  ],
  "sources": [
    "NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8: pound, ounce, grain, short ton, long ton, metric ton. https://www.nist.gov/pml/special-publication-811",
    "UK Weights and Measures Act 1985, Schedule 1, Part VI: 1 stone = 14 pounds. https://www.legislation.gov.uk/ukpga/1985/72/schedule/1"
  ],
  "related": [
    "kg-to-lbs",
    "lbs-to-kg",
    "kg-to-lbs-and-oz",
    "tons-to-kg",
    "unit-converter"
  ],
  "changelog": []
}