Online maths converters

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Are you bored? Try the Fun Stuff. Was this site helpful? Link to Us Donate. In the past, many systems of measurement were defined on a local level, and could be based on factors as arbitrary as the length of a king's thumb. While this may work on a local level, when considering trade, as well as science, having systems of units based on units that others may not be able to relate to or understand makes interaction difficult.

As such, the development of more universal and consistent systems developed over time. Today, some of the systems of units in use include the metric system, the imperial system, and the United States customary units. The International System of Units SI is the standard metric system that is currently used, and consists of seven SI base units of length, mass, time, temperature, electric current, luminous intensity, and amount of substance.

Although SI is used almost universally in science including in the US , some countries such as the United States still use their own system of units. This is partly due to the substantial financial and cultural costs involved in changing a measurement system compared to the potential benefit of using a standardized system. As such, many unit converters including this Conversion Calculator exist, and will continue to do so to ensure that people globally are able to communicate different measurements effectively.

The Arabs used coins as a measurement of units of weight since a minted coin could not easily be cut or shaved to reduce its weight, and thus provided a measurable standard. They used a coin called a silver dirhem as a basic measure of weight, which had a weight roughly equivalent to 45 fully grown grains of barley. Ten dirhems comprised a Wukryeh, which was translated into Latin as an "uncia" — the origin of the word "ounce. Over time, trade spread from the Mediterranean area to Europe, including the northern German City States.

As a result, a pound, 16 ounces of silver, or grains, became a commonly used measure in many regions. While England also adopted this measure, a shortage of silver caused King Offa to reduce the measurement of the pound to grains in order to use smaller coins.

Eventually, when William the Conqueror became King of England, he retained the grain pound for minting coins, but reverted to the grain pound for other purposes. Though many countries used the pound from that point onward, including England the British pound sterling, or GBP was equal to one pound-weight of silver in King Offa's time , the avoirdupois weight system was adopted during the reign of Queen Elizabeth in the 16th century.

It was a system based on the weight of coal, and its name was derived from the French phrase "avoir de pois" goods of weight or property. The avoirdupois was equivalent to 7, grains, drams of Since , the avoirdupois pound has been officially defined in most English-speaking countries as 0. Different systems of measurement also developed over time in Asian countries. For example, in ancient India, a measure of weight called the "Satamana" was used, and was equal to the weight of gunja berries.

The measurement of weight was based on the shi, which was equivalent to approximately pounds.