List of Basic Weight Conversions

More than 100 different measurements exist throughout the world, many being country specific. Only a few of these classify as common mass measurements, while the others remain as infrequently used, outdated or irrelevant. Most basic weight measurements fit into the category of metric, U.S. or imperial. Carat (when referring to mass) is also part of the metric system, but measures the weight of only gemstones and pearls.

Metric

The metric system of weight dates to the 18th century, and exists as a standard in all the countries of the world. Metric weight includes the metric ton, kilogram, gram and milligram. One metric ton is 1,000 kilograms, one kilogram is 1,000 grams and one gram is 1,000 milligrams. The metric ton is comparable to the imperial short ton, one weighing 1.102 short tons. One kilogram is 2.204 pounds or 35.274 ounces.

U.S. Customary

The U.S. Customary system has its origin in the imperial system, though some measurements vary slightly. The short ton, often called just "ton," differs from the ton in the imperial measurements. The most common weights in the U.S. customary system are the short ton, pound and ounce. One short ton is equal to 2,000 pounds or 32,000 ounces. One pound is, therefore, 16 ounces. One short ton is 0.907 metric tons, one pound is 0.453 kilograms and one ounce is 28.349 grams.

Imperial

The imperial system of measurement began its use in the British Empire in 1824. It is similar to the currently used U.S. customary system, however, incorporates the measurement of "stone" and uses a different mass for its ton. One stone equals 14 pounds, 224 ounces or 6.35 kilograms. An imperial ton is equal to 1.016 metric tons or 1.12 short tons.

Small Weight Measurements

The carat is the smallest of the metric weights, being equal to 200 milligrams. Its close equivalent in the imperial and U.S. customary system is the grain, at 3.086 grains to the carat or 0.324 carats to the grain. The U.S. customary system also has the slightly larger weight of dram (256 drams to the pound), which is called drachm in the imperial system.