{
  "schemaVersion": 1,
  "slug": "kg-lbs-calculator",
  "category": "conversion",
  "kind": "implementation",
  "independentValidation": false,
  "implementationHash": "898878d72c2c03fca788e0d69c878727c5ed0f8e6d565f43ae14b736794fd489",
  "provenance": "Generated from the calculation contract used by the published page. Publication is not external validation.",
  "sourceFiles": [
    "data/calculators/kg-lbs-calculator.json",
    "src/engine.js"
  ],
  "runtimeSource": "/sources/engine.txt",
  "runtimeHash": "5c888d8898afbdee36267bb9977829e1e2ac568f6677c8ee87469c139864645c",
  "scope": "The compute function records implemented equations, constants, lookup tables and custom rules. Inputs record defaults and allowed values; outputs record precision and units. Defaults are examples, not recommendations. General background references are not evidence for this specific algorithm.",
  "publishedFormula": {
    "formula": "lb = kg ÷ 0.45359237; kg = lb × 0.45359237; st = kg ÷ 6.35029318",
    "vars": [
      [
        "kg",
        "Kilograms"
      ],
      [
        "lb",
        "Pounds"
      ],
      [
        "st",
        "Stones"
      ],
      [
        "g",
        "Grams"
      ]
    ],
    "note": "Exact international conversion factors; grams = kg × 1000."
  },
  "externalEvidence": {
    "reviewedAt": "2026-10-04",
    "sources": [
      {
        "name": "NIST SP 811 — Conversion factors by quantity",
        "url": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b9"
      }
    ],
    "basis": "1 avoirdupois pound = 0.45359237 kg.",
    "limitations": "Only the displayed unit definitions are converted; rounding and measurement uncertainty are separate.",
    "implementationHash": "898878d72c2c03fca788e0d69c878727c5ed0f8e6d565f43ae14b736794fd489",
    "domain": "conversion"
  },
  "contract": {
    "compute": "const F={\"kg\":1,\"lb\":0.45359237}, U={\"kg\":\"kg\",\"lb\":\"lb\"}, L={\"kg2lb\":[\"kg\",\"lb\"],\"lb2kg\":[\"lb\",\"kg\"]}; const pair=Object.prototype.hasOwnProperty.call(L,direction)?L[direction]:[from,to], source=pair[0], target=pair[1]; if(!Number.isFinite(value)||value<-1000000000||value>1000000000||!Object.prototype.hasOwnProperty.call(F,source)||!Object.prototype.hasOwnProperty.call(F,target))return {\"result\":null,\"stones\":null,\"grams\":null,\"__error\":\"inputError\"}; const base=value*F[source], out=(function(value,direction){const kg = direction === 'kg2lb' ? value : value*0.45359237; return { result: direction === 'kg2lb' ? kg/0.45359237 : kg, stones: kg/6.35029318, grams: kg*1000 };})(base/F[\"kg\"],\"kg2lb\"); if(out.__error)return {...{\"result\":null,\"stones\":null,\"grams\":null},...out}; out.result=value*(F[source]/F[target]);out.__resultUnit=U[target];out.__unitRatio=F[target]/F[source];return out;",
    "inputs": [
      {
        "name": "value",
        "type": "number",
        "default": 70,
        "min": -1000000000,
        "max": 1000000000,
        "step": 0.01,
        "requiredValue": true,
        "strictRange": true
      },
      {
        "name": "direction",
        "type": "select",
        "default": "auto",
        "options": [
          {
            "value": "auto"
          },
          {
            "value": "kg2lb"
          },
          {
            "value": "lb2kg"
          }
        ],
        "showWhen": {
          "from": []
        }
      },
      {
        "name": "precision",
        "type": "select",
        "default": 4,
        "options": [
          {
            "value": 0
          },
          {
            "value": 2
          },
          {
            "value": 4
          },
          {
            "value": 6
          }
        ]
      },
      {
        "name": "from",
        "type": "select",
        "default": "kg",
        "options": [
          {
            "value": "kg"
          },
          {
            "value": "lb"
          }
        ]
      },
      {
        "name": "to",
        "type": "select",
        "default": "lb",
        "options": [
          {
            "value": "lb"
          },
          {
            "value": "kg"
          }
        ]
      }
    ],
    "outputs": [
      {
        "name": "result",
        "precision": 4,
        "unit": "",
        "precisionField": "precision",
        "unitField": "__resultUnit",
        "trimTrailingZeros": true,
        "notation": "auto"
      },
      {
        "name": "stones",
        "precision": 3,
        "unit": "st",
        "notation": "auto"
      },
      {
        "name": "grams",
        "precision": 0,
        "unit": "g",
        "notation": "auto"
      }
    ],
    "interpret": null
  }
}