Convert Stones to Kilograms

The Stone (symbol: st) is a unit of weight & mass. A British imperial unit of mass equal to exactly 14 pounds (= 6.35029318 kilograms per NIST SP 811). The stone is still the everyday unit for personal body weight in the United Kingdom and Ireland — colloquial usage routinely says 'I weigh 12 stone' rather than 168 pounds or 76 kilograms — and British bathroom scales typically display stones and pounds (e.g., '11 st 8 lb') as the primary scale alongside kilograms. Officially abolished from UK commerce in 1985 under the Weights and Measures Act amendments, the stone nonetheless remains cultural shorthand in British medical charts, GP consultations, fitness and weight-loss programs, and casual conversation about weight. Equine and livestock weights in Britain and Ireland are also still sometimes quoted in stones at agricultural auctions and equestrian weighing. Reference values: average UK adult male body weight ~12 st 5 lb (78 kg), average UK adult female ~11 st 2 lb (70 kg) per ONS Health Survey England. Convert stones to kg by multiplying by 6.350; to lb by multiplying by 14.

Stones are commonly used in cooking, shipping, fitness, and scientific research.

The Kilogram (symbol: kg) is a unit of weight & mass. The SI base unit of mass per ISO 80000-3 §3-4 and BIPM SI Brochure 9th edition, redefined in 2019 by fixing the Planck constant h = 6.62607015 × 10⁻³⁴ J·s exactly. The kilogram was historically defined (1889-2019) by the International Prototype of the Kilogram (IPK) — a platinum-iridium cylinder at BIPM Pavillon de Breteuil in Sèvres, France — but the 2019 redefinition tied it to a fundamental constant, removing the only remaining artifact-based SI base unit. The kilogram is realized in practice by the Kibble (watt) balance method at NIST, NPL, NIM, NRC Canada, KRISS, and ~12 other national metrology institutes worldwide. Reference values: 1 kg of water at 4°C occupies almost exactly 1 liter (a design feature of the original 1795 metric system); typical newborn human 3.0-3.5 kg; ICE-vehicle dry curb weight 1,200-2,500 kg; commercial aircraft Boeing 737 MTOW 79,000 kg, Airbus A380 575,000 kg; cargo container TEU full load 24,000 kg gross. Kilograms are the global standard for: scientific measurement, shipping weights per IMO + IATA + ICAO, food packaging in most of the world per EU Reg 1169/2011 + Codex Alimentarius, body weight outside the US (clinical BMI calculations require kg per WHO), and bulk industrial trade.

It belongs to the metric measurement system.

Kilograms are commonly used in cooking, shipping, fitness, and scientific research.