How the Weight Converter Works
This tool converts between 9 common weight and mass units across both metric and imperial systems. Select a source unit, enter a value, and pick a target unit — the result updates instantly without clicking any button.
The metric side includes micrograms, milligrams, grams, and kilograms. The imperial side includes ounces, pounds, and tons. Stone (used in the UK for body weight) and metric tons are also supported for international use.
Common Weight Conversions
- Kilograms to Pounds: 1 kg = 2.20462 lbs. Multiply kg by 2.205.
- Pounds to Kilograms: 1 lb = 0.45359 kg. Divide pounds by 2.205.
- Ounces to Grams: 1 oz = 28.3495 g. Multiply oz by 28.35.
- Stone to Kilograms: 1 stone = 6.35029 kg. Used in the UK and Ireland for body weight.
Metric vs Imperial Weight Units
Grams and kilograms are the standard for science, medicine, and most countries worldwide. Pounds and ounces are used in the United States for food, body weight, and shipping. This converter handles both systems so you can switch between recipes, shipping labels, and scientific data without manual math.
Common Weight Units
Weight is measured using several different units depending on the context and country. The metric system uses grams (g) and kilograms (kg) as standard units, with metric tons (1,000 kg) for large weights. The imperial system uses ounces (oz), pounds (lb), and US tons (2,000 lb). The stone (14 lb) is used in the UK and Ireland for body weight. Micrograms and milligrams are used for scientific and pharmaceutical measurements where precision is critical.
How Weight Conversion Works
Weight conversion is performed by multiplying the source value by a fixed conversion factor. For example, to convert 5 kilograms to pounds, multiply 5 by 2.20462 to get 11.02 pounds. All weight units have defined relationships to the kilogram, which is the SI base unit of mass. The converter handles conversions between all 9 supported units instantly, but understanding the factors helps you verify results and perform quick mental estimates when needed.
Practical Examples
- Cooking: Recipes may use grams (Europe), ounces (US), or cups (volume-based). Converting 250 g of flour to ounces gives about 8.8 oz. Accuracy matters in baking.
- Body weight: Most countries use kilograms, while the US uses pounds, and the UK uses stone. A 70 kg person weighs 154 lbs or 11 stone. Medical records may require conversion between systems.
- Shipping: Parcel shipping costs depend on weight. International shipping requires accurate conversion between kg and lbs. A 5 kg package is about 11 lbs for US-based carriers.
- Fitness: Gym weights use kilograms in most countries but pounds in the US. A 20 kg barbell plate equals 44 lbs. Knowing conversions helps when following international workout programs.
Difference Between Weight and Mass
Weight and mass are often used interchangeably in everyday conversation but are scientifically distinct. Mass is the amount of matter in an object, measured in kilograms (kg) or grams (g). Weight is the force of gravity acting on that mass, measured in newtons (N). Your mass stays the same whether you are on Earth, the Moon, or in space. Your weight changes because gravity changes. This converter works with weight units as used in everyday life, where the distinction matters less because gravity is essentially constant on Earth's surface.