Stones to Kilograms Converter

How to Convert Stones to Kilograms

To convert a weight measurement from stones to kilograms, multiply the weight by the conversion factor. Since one stone is equal to 6.350293 kilograms, you can use this formula:

The weight in kilograms is equal to the stones multiplied by 6.350293.

How Many Kilograms Are in a Stone?

There are 6.350293 kilograms in one stone.

What Is a Stone?

The stone (symbol: st) is an imperial unit of weight equal to exactly 14 pounds (6.35029318 kilograms). It is primarily used in the United Kingdom and Ireland for expressing human body weight. In the UK, it is common for people to describe their weight in stones and pounds (e.g., “I weigh 11 stone 4 pounds” meaning 11 × 14 + 4 = 158 lb or about 71.7 kg). This usage is deeply embedded in British culture and persists despite the official adoption of the metric system. Historically, the stone varied in weight depending on the commodity being weighed and the region. Stones for wool, cheese, meat, and other goods had different defined weights. The modern stone of 14 pounds was standardised in 1835 by the British Weights and Measures Act. The stone is not commonly used outside the UK and Ireland. In the US, body weight is typically expressed in pounds only, while in most other countries, kilograms are used. However, the stone remains popular in British media, health services, and everyday conversation.

One stone is equal to:

• 14 pounds (lb)
• 224 ounces (oz)
• 6.350293 kilograms (kg)
• 6,350.29 grams (g)
• 0.00635 metric tons (MT)
• 0.00700 tons (t)
• 0.00625 long tons (lt)
• 31,751.5 carats (ct)

What Is a Kilogram?

The kilogram (symbol: kg) is the SI base unit of mass. Since 2019, it has been defined in terms of the Planck constant (h = 6.62607015 × 10⁻³⁴ J·s), replacing the previous definition based on a physical platinum-iridium cylinder stored in Paris. The kilogram is the fundamental unit of mass in science and the standard unit for everyday weighing in most countries. Body weight, food products, luggage allowances, and industrial materials are measured in kilograms throughout the metric world. One kilogram equals exactly 1,000 grams, approximately 2.20462 pounds, or about 35.274 ounces. The kilogram is the only SI base unit that includes a prefix (“kilo”) in its name, a historical artifact from when the gram was considered too small for practical use. In everyday terms, a litre of water at 4 °C has a mass of approximately 1 kg. A standard bag of sugar or flour is typically 1 kg in metric countries. A newborn baby weighs approximately 3–4 kg.

One kilogram is equal to:

• 1,000 grams (g)
• 1,000,000 milligrams (mg)
• 2.204623 pounds (lb)
• 35.27396 ounces (oz)
• 0.001 metric tons (MT)
• 0.157473 stones (st)
• 5,000 carats (ct)

Understanding Weight and Mass Units

Weight and mass are related but distinct concepts. Mass is the amount of matter in an object and is constant regardless of location. Weight is the force of gravity acting on that mass and varies with gravitational field strength. In everyday language, “weight” and “mass” are used interchangeably, and the units on this page measure mass.

Weight and mass units have evolved from different historical measurement systems, resulting in a rich variety of units still in use today.

Major Unit Systems

• Metric / SI units: The kilogram (kg) is the SI base unit of mass. Grams (g) and milligrams (mg) are derived using standard prefixes. The metric ton (tonne, 1,000 kg) is used for large masses.
• US customary / Imperial units: The pound (lb) is the primary unit, with 16 ounces per pound. The US short ton (2,000 lb) and the imperial long ton (2,240 lb) are used for large masses. The stone (14 lb) is used in the UK for body weight.
• Specialised units: The carat (0.2 g) is used for gemstones. The Calorie (kcal) is used as a proxy for weight change based on the 3,500 kcal per pound approximation.

Key Conversion Relationships

• 1 pound (lb) = 453.59237 grams (exact by international agreement)
• 1 kilogram (kg) = 2.204623 pounds
• 1 ounce (oz) = 28.349523 grams = 1/16 pound
• 1 stone (st) = 14 pounds = 6.350293 kg
• 1 US ton (t) = 2,000 pounds = 907.185 kg
• 1 long ton (lt) = 2,240 pounds = 1,016.047 kg
• 1 metric ton (MT) = 1,000 kg = 2,204.623 pounds
• 1 carat (ct) = 0.2 grams = 200 milligrams (exact)

Tips for Weight Conversions

• The most important conversion to remember: 1 kg ≈ 2.2 lb. Multiply kilograms by 2.2 for a quick pounds estimate, or divide pounds by 2.2 for kilograms.
• For ounces to grams: 1 oz ≈ 28.35 g. Multiply ounces by 28 for a rough gram estimate.
• UK body weight in stones: divide pounds by 14. For example, 154 lb = 11 stone.
• Don’t confuse the three types of “ton”: US short ton = 2,000 lb, metric ton = 2,204.6 lb, long (imperial) ton = 2,240 lb.
• The metric ton is about 10% heavier than the US short ton. When reading international commodity prices, check which ton is being used.
• For gemstones: 1 carat = 0.2 grams exactly, so 5 carats = 1 gram. A 1-carat diamond is about the size of a pencil eraser top.
• Don’t confuse avoirdupois ounces (28.35 g, for general weighing) with troy ounces (31.10 g, for precious metals) or fluid ounces (a volume measure).
• The Calorie-to-weight conversion (3,500 kcal per pound) is a nutritional approximation, not a physical constant. It is useful for rough weight-loss estimates but not for precise calculations.

Stones to Kilograms Conversion Table

The following table shows conversions from stones to kilograms.

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