Apparently, there are 3 main systems of measurement : Metric, Imperial system of measurement and the USA system of measurement. The Imperial is different from the USA (For example, the USA pint has 16 ounces whereas the Imperial pint has 20 ounces)....what a mess!!:-S Advantages of Metric System Simplicity. The Metric system has only 7 basic measures, plus a substantial number of measures using various combinations of these base measures. The imperial system and the USA system have over 300 different measures, of which many are ambiguous. For example, there are eight different definitions of ton (including the 'short ton' and the 'long ton'), all of which differ in weight. There are also eight different definitions of barrel, five different definitions of bushel, three different definitions of mile (international, nautical, and US Survey). The USA gallon is smaller than the Imperial gallon, and all measures which are multiples or subdivisions of the gallon (e.g. pint, quart) likewise are inconsistent between the USA and the UK. Not only are the USA and UK pints different in size, but there are also differences between 'dry pints' and 'liquid pints'. Ease of calculation. All the units in the metric system are multiplied by 10 (to make larger units) or divided by 10 (to make smaller units). For example a kilometer is 1000 meters (10 * 10 * 10). It's nearest equivalent is a mile which is 5280 feet (8 * 10 * 22 * 3; based on the calculation that a mile is 8 furlongs, 10 chains to a furlong, 22 yards to a chain, 3 feet to a yard). Although complex calculations can be done using the Imperial or USA system, almost all calculations can be done easier and faster in the metric system. International Standard. With the exception of the USA, all major countries have converted to the metric system (although in some countries, such as the UK, the conversion to metric is not yet complete). Consequently, for any international communication (trade, science, etc.) the metric system is the most widely used and accepted.