Weights and measures refer to legal units of measurement in different countries. The science of developing universally accepted weights and measures is called as metrology. The institution that implements the S.I. unit of measurement worldwide is The Bureau International Des Poids et measures (BIPM).

The SI unit of weight is the Kilo Gram (KG). The other conversion measures used in the world to measure weight are Carats, Grains, Grams, Ounces, Pounds, Slugs, stones, and Tons.

The Kilogram is the basic unit of mass. It is the mass of an international prototype in the form of a platinum-iridium cylinder kept at Sevres in France. It is now the only a basic unit still defines in terms of a material object and also the only one with a pre-fix, kilo already attached.

The U.S system of measurement is very similar to that of the U.K. Weight is measured in the following way-

437.5 grams=1 ounce

16 ounces= 1 pound

14 pounds=1stone

100 pounds=1 hundred weight (cwt)

20 cwt = 1 ton (2000 pounds)

The conversion scale is as follows: Kilogram=

Carats X .0002

Grain X .000 064

Gram X .001

Ounce X 0.028

Pounds X 0.453

Slugs X 14.593

Stones X 6.350

Tons X 1016.046

Tonnes X 1000

Conversion weight scales are adept at calculating the various values of a single weight reading in different weight measures. This helps in international, universal as well as precise readings of weight measures for various purposes including commercial, medical, sports and other uses.

The grain was the earliest unit of mass and was used to weigh silver and gold. The Pound was derived from The Mina used in early civilizations. Smaller unit was the Shekel and a larger unit the Talent. The Carat is a unit for measuring gemstones that had its origin in the Carob seed and was later standardized at 0.2 gram. When weighing of goods began, units of mass based on volume of grain or water were developed. The stone, Quarter and ton were large units used in Britain. But today only stone is used to measure

Personal body weight.

Today the market has many scales that have the function of weight conversion. Digital scales are available that can make readings for ounce, carats, grams, and pounds and are equivalent to several weighing machines rolled into one. An Acculab Vicon Digital Balance for instance weighs in oz., Lb, dwt, grains, Newtons, carats, Taels plus user defined units.