Converter category
Weight Converter
Convert milligrams, grams, kilograms, ounces, pounds, stone, tons, carats, troy ounces, and more with precise mass conversion factors.
Universal Weight Converter
About weight conversions
Weight conversions are part of everyday life, from checking luggage before a flight and following a recipe to tracking fitness progress and shipping packages internationally. Our weight converter covers metric units such as milligrams, grams, kilograms, and metric tons, plus Imperial and US customary units including ounces, pounds, stone, short tons, and long tons. It also includes specialized units for precious metals like troy ounces and pennyweights, scientific mass such as atomic mass units, and historical grains. Every conversion uses internationally recognized standards, so whether you are cooking, trading, studying, or traveling, you get an accurate result instantly.
Most popular weight conversions
Available units
Popular weight conversions (19 total)
Unit definitions
Milligram (mg)
A milligram is one thousandth of a gram. A grain of salt weighs about 60 mg.
Origin: Part of the metric system where milli- denotes one-thousandth.
Current use: Pharmaceutical dosages, Nutrition labels, Laboratory measurements
Gram (g)
A gram is one thousandth of a kilogram. A paperclip weighs about one gram.
Origin: The gram was defined in 1795 as the mass of one cubic centimeter of water.
Current use: Cooking ingredients, Mail postage, Small item weights
Kilogram (kg)
The kilogram is the SI base unit of mass. One kilogram equals approximately 2.205 pounds.
Origin: Originally defined as the mass of one liter of water. Since 2019, defined by the Planck constant.
Current use: Body weight, Grocery shopping, Scientific measurements
Ounce (oz)
An ounce is 1/16 of a pound, approximately 28.35 grams. Theavoirdupois ounce is used for everyday weight measurements.
Origin: From the Latin uncia meaning one-twelfth. The avoirdupois system was standardized in the 16th century.
Current use: Food packaging, Precious metals, Postal weights
Pound (lbs)
A pound is 16 ounces or approximately 454 grams. It is the primary unit of weight in the US customary system.
Origin: The word pound comes from Latin pondus (weight). The avoirdupois pound was standardized in the 1300s.
Current use: Body weight (US), Food products, Shipping weights
Stone (st)
A stone is 14 pounds or 6.35 kilograms. It is commonly used in the UK and Ireland for body weight.
Origin: Historically used for weighing agricultural commodities. One stone was originally the weight of a stone of merchandise.
Current use: Body weight (UK/Ireland), Horse racing
Metric Ton (t)
A metric ton is 1000 kilograms or approximately 2205 pounds. It is the standard unit for large weights worldwide.
Origin: Part of the metric system. Also called a tonne to distinguish from the shorter US ton.
Current use: Shipping containers, Heavy machinery, Cargo weights
Short Ton (short tn)
A short ton is 2000 pounds or 907 kilograms. It is commonly used in the United States.
Origin: Also called a US ton, distinguished from the longer Imperial ton used in the UK.
Current use: US shipping, Construction materials, Heavy haulage (US)
Long Ton (long tn)
A long ton is 2240 pounds or 1016 kilograms. It is used in the UK and some Commonwealth countries.
Origin: Also called the Imperial ton or weight ton. Historically used for commodities like coal and grain.
Current use: UK shipping, Commodity trading, Historical cargo weights
Carat (ct)
A carat is 200 milligrams, used worldwide for measuring gemstones and pearls.
Origin: From the Arabic qirrat meaning small weight. Originally based on carob seeds.
Current use: Gemstone weighing, Jewelry grading, Pearl measurement
Grain (gr)
A grain is exactly 64.8 milligrams, based on the weight of a grain of wheat.
Origin: One of the oldest weight units, based on actual grain weights.
Current use: Bullet and ammunition weights, Metallic weighing, Historical measurements
Troy Ounce (oz t)
A troy ounce is 31.1 grams, used for precious metals. Heavier than a regular ounce (28.35g).
Origin: Originates from Troyes, France, medieval trading city. Standard for precious metals since the 16th century.
Current use: Gold and silver trading, Coin weights, Jewelry
Pennyweight (dwt)
A pennyweight is 1/20 of a troy ounce, approximately 1.56 grams.
Origin: Based on the weight of an English penny. Used in dentistry and jewelry.
Current use: Jewelry manufacturing, Dentistry, Gold prospecting
Atomic Mass Unit (u)
An atomic mass unit is 1/12 of a carbon-12 atom, approximately 1.66×10⁻²⁷ kg.
Origin: Defined by the International Union of Pure and Applied Chemistry.
Current use: Chemistry, Molecular biology, Atomic physics
Common uses for weight conversions
Weight conversions are used in cooking and baking, fitness tracking, international shipping, scientific research, jewelry trading, agriculture, and travel baggage checks.
Frequently asked questions about weight
How many pounds are in 1 kilogram?+
1 kilogram equals approximately 2.20462 pounds.
What is the difference between mass and weight?+
Mass is the amount of matter in an object and stays the same everywhere. Weight is the force of gravity on that mass, so it changes slightly with location.
Which weight units does this converter support?+
It supports metric, Imperial, US customary, precious metal, scientific, and historical units — over 15 in total.