A weight converter changes a quantity of mass from one unit into another — kilograms to pounds, grams to ounces, or tonnes to US tons. It is useful for cooking with foreign recipes, reading body weight given in stone or pounds, checking luggage and shipping limits, and comparing product weights across metric and imperial labels. This tool covers milligrams, grams, kilograms, metric tonnes, ounces, pounds, stones and US tons.
The formula. Every value is converted through one base unit, the kilogram. The exact factors are 1 g = 0.001 kg, 1 mg = 0.000001 kg, 1 tonne = 1,000 kg, 1 ounce = 0.028349523 kg, 1 pound = 0.45359237 kg, 1 stone = 6.35029318 kg and 1 US ton = 907.184 kg. A value is multiplied to kilograms, then divided by the target unit's factor: result = value × factor(from) ÷ factor(to).
Worked example. To convert 5 kilograms of flour to pounds, divide by 0.45359237: 5 ÷ 0.45359237 ≈ 11.02 pounds. For a person weighing 80 kg in stones, 80 ÷ 6.35029318 ≈ 12.6 stone, which is about 12 stone 8 pounds.
Where it's used. Mass conversion is everyday work: kitchen scales switch between grams and ounces, gyms and clinics record body weight in kg, lbs or stone, many airlines limit cabin baggage to around 7 kg (about 15.4 lb), and freight is priced by the metric tonne. Postage, parcel couriers and precious-metal pricing per gram all rely on accurate weight conversion.