Weight Converter
Convert kilograms, pounds, ounces and more.
Understanding Weight Converter
The Weight Converter allows you to convert a measurement from one commonly used unit of mass into another. It supports metric units such as milligrams, grams, kilograms, and metric tonnes, as well as commonly used imperial and U.S. customary units such as pounds, ounces, and stone. Converting between these units is useful whenever measurements are presented using different systems or when a specific unit is required for a calculation, product specification, recipe, shipment, or other practical purpose.
In everyday language, the word "weight" is commonly used when referring to how heavy an object is. In physics, however, mass and weight are technically different quantities. Mass describes the amount of matter in an object and is commonly measured in kilograms, grams, pounds, or ounces. Weight is technically a force produced by gravity and is measured in newtons. Most everyday weight-conversion tasks are actually conversions between units of mass, which is why this calculator uses standard mass conversion factors.
How to work through the calculation
Weight Converter is most useful when the measurements you enter are taken using the same units and definitions shown beside each field. The calculator asks for values such as From, To, Value; enter the measurements as accurately and consistently as possible rather than rounding them before calculation.
A useful detail to keep in mind
The number produced by this tool should be read in the context of the inputs and the method used by the calculator. A calculated health or fitness figure can be useful for education, planning, or tracking change over time, but it does not by itself describe every aspect of an individual’s health.
About Weight Converter
The Weight Converter allows you to convert a measurement from one commonly used unit of mass into another. It supports metric units such as milligrams, grams, kilograms, and metric tonnes, as well as commonly used imperial and U.S. customary units such as pounds, ounces, and stone. Converting between these units is useful whenever measurements are presented using different systems or when a specific unit is required for a calculation, product specification, recipe, shipment, or other practical purpose.
In everyday language, the word "weight" is commonly used when referring to how heavy an object is. In physics, however, mass and weight are technically different quantities. Mass describes the amount of matter in an object and is commonly measured in kilograms, grams, pounds, or ounces. Weight is technically a force produced by gravity and is measured in newtons. Most everyday weight-conversion tasks are actually conversions between units of mass, which is why this calculator uses standard mass conversion factors.
The metric system is based on the kilogram as its primary unit of mass, with related units connected through powers of ten. One kilogram equals 1,000 grams, while one gram equals 1,000 milligrams. Metric tonnes are used for much larger quantities, with one metric tonne equal to 1,000 kilograms. These relationships make conversions within the metric system straightforward.
Imperial and U.S. customary units use different relationships. A pound is divided into 16 ounces, while a stone is equal to 14 pounds. The metric tonne is different from the imperial ton and the U.S. short ton, so it is important to identify the correct unit when converting large quantities. This calculator specifically uses the metric tonne for the "t" unit.
Weight and mass conversions are commonly used in cooking, nutrition, fitness, medicine, shipping, manufacturing, engineering, science, retail, travel, and everyday measurements. For example, a person's weight may be recorded in kilograms in one country and pounds in another, while a recipe may list ingredients in grams or ounces. Shipping and industrial applications may require kilograms or metric tonnes for larger quantities.
The accuracy of a conversion depends on using the correct unit and conversion factor. The underlying physical quantity does not change during a unit conversion; only the numerical representation changes. A larger numerical value may therefore appear when converting into a smaller unit, while a smaller numerical value appears when converting into a larger unit.
How Weight Conversion Works
This calculator uses kilograms as the internal base unit. The entered value is first converted into kilograms using the standard conversion factor for the selected starting unit. The kilogram value is then converted into the selected target unit. This two-step approach allows every supported unit to be converted consistently into every other supported unit.
Value in kilograms = Original Value × Conversion Factor
Converted Value = Kilograms ÷ Target Unit Factor
Common Weight Conversions
1 kilogram = 1,000,000 milligrams
1 kilogram × 2.20462 pounds
1 kilogram × 35.274 ounces
1 kilogram × 0.157473 stone
1 metric tonne = 1,000 kilograms
Examples
Original Weight: 10 kg
Conversion Factor: 1 kg = 2.20462 lb
10 × 2.20462 ≈ 22.0462 lb
Result: 10 kg ≈ 22.0462 lb
Original Weight: 150 lb
Conversion Factor: 1 lb = 0.453592 kg
150 × 0.453592 ≈ 68.0388 kg
Result: 150 lb ≈ 68.0388 kg
Original Weight: 500 g
First convert grams to kilograms:
500 ÷ 1,000 = 0.5 kg
Then convert kilograms to ounces:
0.5 × 35.274 ≈ 17.637 oz
Result: 500 g ≈ 17.637 oz
Choosing the Right Unit
The most appropriate unit depends on the size and purpose of the measurement. Milligrams are useful for very small quantities, grams are common for food ingredients and small objects, and kilograms are widely used for body weight and everyday larger masses. Pounds and ounces are frequently encountered in the United States and some other countries, while stone is traditionally used for body weight in the United Kingdom and Ireland. Metric tonnes are generally more suitable for heavy commercial, industrial, and transportation quantities.
Weight Conversion Reference
The following relationships can be used as quick reference values:
1 st = 14 lb
1 t = 1,000 kg
1 kg = 1,000 g
1 g = 1,000 mg
Understanding the Result
The result represents the same underlying mass expressed in the unit selected in the "To" field. For example, converting 5 kilograms to pounds does not change the amount of mass; it simply expresses the same measurement using pounds instead of kilograms. The calculator also provides several common equivalents so that the converted value can be easily compared across different measurement systems.
Because the displayed value is rounded for readability, the last decimal places may differ slightly from results shown by another calculator that uses a different rounding setting. The conversion itself is based on internationally established relationships between the supported units.
Disclaimer
This calculator is intended for informational purposes only. While we strive for accuracy, we cannot guarantee that every result is correct for every situation.