The weight calculator here can be used for converting values between common mass and weight units. You have to enter one value and the calculator shows its equivalent in the other.
If you look at the early Egyptian and Babylonian records, they indicate that people used to measure weight originally by container capacities. The common containers were something like clay, metal or gourds vessels. They used to fill these containers with different plant seeds which they used to count for measuring volumes. As scales were developed for weighing different items, stones and seeds became the standards. For example, "carat" is the unit that is still used to measure gems and it was derived from carob seed.
Babylonians first invented talent as basic unit for weight and, depending on the sexagesimal they had, it was divided in equal parts of that particular number.
It equaled amount of water required for filling an amphora.
Same sort of weight measurement was used by the Greeks. However, it was changed by Romans. They used 'uncia' as basic unit for weight measurement. In fact, the word 'ounce' which is currently used as a unit for weight measurement was derived first from uncia. Uncia is considered twelfth part of Roman 'foot' called 'pes'. The word inch also came from uncia. These same words were used by the Romans for ounce and they used to measure it with a technique Arabs used to implement for the same.
Arabs, at that time, used to determine one silver Dirhem with the help of 45 fully grown barley grains. 10 such Dirhems combined to make Wukryeh comprising 450 grains, which was called one ounce from Latin 'uncia' or 12th, and that’s the name used genetically to represent such type of volume or weight.
Well, this weight calculator is not for measuring an individual's weight. Rather, you can use it for converting an individual's weight into different units. The working of the calculator is quite simple as well. You can enter the value of weight in a particular unit that you know and select the unit that you want to convert it to in the other list. Just hit the calculate button and the calculator will tell you the equivalent value for the provided weight in the desired unit. Inter-conversion between 17 different weight units is possible with this weight calculator and the results provided are accurate to several decimal points.