{
  "version": "2026-10-31",
  "method": "Calcul décimal ; différence B − A et écart relatif (B − A)/A × 100. Six scénarios choisis, sans mesure de terrain ni comparaison de logiciels.",
  "rows": [
    {
      "id": "gallons",
      "title": "20 gallons : US liquide ou impérial",
      "conventionA": "US liquide",
      "conventionB": "impérial",
      "unit": "L",
      "quantity": "20",
      "factorA": "3.785411784",
      "factorB": "4.54609",
      "resultA": "75.708235680",
      "resultB": "90.92180",
      "difference": "15.213564320",
      "relativeDifferencePercent": "20.0950",
      "source": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "limit": "Les deux nombres désignent des conventions différentes, pas une incertitude de mesure.",
      "page": "/mathematique/gallon-us-imperial.html"
    },
    {
      "id": "tonnes",
      "title": "2 tonnes : métriques ou short tons",
      "conventionA": "tonne métrique",
      "conventionB": "short ton US",
      "unit": "kg",
      "quantity": "2",
      "factorA": "1000",
      "factorB": "907.18474",
      "resultA": "2000",
      "resultB": "1814.36948",
      "difference": "-185.63052",
      "relativeDifferencePercent": "-9.2815",
      "source": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "limit": "Lire le nom complet de l’unité sur le document.",
      "page": "/poids/tonne-short-ton.html"
    },
    {
      "id": "cuilleres",
      "title": "4 cuillères à soupe : métriques ou US",
      "conventionA": "cuillère métrique",
      "conventionB": "tablespoon US",
      "unit": "mL",
      "quantity": "4",
      "factorA": "15",
      "factorB": "14.78676478125",
      "resultA": "60",
      "resultB": "59.14705912500",
      "difference": "-0.85294087500",
      "relativeDifferencePercent": "-1.4216",
      "source": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "limit": "Les ustensiles réels peuvent différer de ces conventions de volume.",
      "page": "/autres/cuillere-soupe-millilitre.html"
    },
    {
      "id": "mois",
      "title": "6 mois : convention de 30 jours ou moyenne grégorienne",
      "conventionA": "mois de 30 jours",
      "conventionB": "mois moyen grégorien",
      "unit": "jours",
      "quantity": "6",
      "factorA": "30",
      "factorB": "30.436875",
      "resultA": "180",
      "resultB": "182.621250",
      "difference": "2.621250",
      "relativeDifferencePercent": "1.4562",
      "source": "https://aa.usno.navy.mil/faq/leap_years",
      "limit": "Aucune de ces moyennes ne remplace deux dates de calendrier.",
      "page": "/temps/mois-calendrier.html"
    },
    {
      "id": "livres",
      "title": "10 livres : facteur exact ou raccourci à 500 g",
      "conventionA": "livre avoirdupois",
      "conventionB": "approximation à 500 g",
      "unit": "g",
      "quantity": "10",
      "factorA": "453.59237",
      "factorB": "500",
      "resultA": "4535.92370",
      "resultB": "5000",
      "difference": "464.07630",
      "relativeDifferencePercent": "10.2311",
      "source": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "limit": "La deuxième colonne est un raccourci volontairement approximatif, pas une autre définition de la livre.",
      "page": "/poids/livre-gramme.html"
    },
    {
      "id": "pieds",
      "title": "5,11 pieds ou 5 pieds 11 pouces",
      "conventionA": "5,11 pieds décimaux",
      "conventionB": "5 pieds 11 pouces",
      "unit": "m",
      "quantity": "1",
      "factorA": "1.557528",
      "factorB": "1.8034",
      "resultA": "1.557528",
      "resultB": "1.8034",
      "difference": "0.245872",
      "relativeDifferencePercent": "15.7860",
      "source": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors",
      "limit": "5,11 × 0,3048 ; (5 × 0,3048) + (11 × 0,0254). La virgule ne sépare pas les unités.",
      "page": "/distance/pied-metre.html"
    }
  ]
}