What is the purpose of metrication?

Answer 1

In general, the purpose of metrication is to convert measurements from a customary system of measurements to the international system of measurements (known as SI and specified by BIPM http://www.bipm.org/en/si/).

Wider purposes include:

• improved trade through the use of a common measurement system
• reduced errors in many aspects of society due to not having to convert between a customary system of measurements and SI (or, even worse, dealing with customary systems that have the same names for things but different values, like the US and UK customary systems).
• reducing mistakes or fraud by moving to a simple system of measurements. A gram of anything is the same as a gram of anything else and a kilogram is always 1,000 grams. Customary systems tend to vary in complex ways such as the name "ounce" having different values depending on whether you're measuring gold (31 g) or lead (28 g) and not being consistent in their multipliers such as a pound of gold (373 g) weighing less than a pound of other things (454 g) even though an ounce of gold weighs more.
• making measurement and calculations involving measurement more accessible. One of the really cool things about metric is that it's a system so, for water, 1 g = 1 mL = 1 cm^3 which makes questions like "this truck can take 2,000 kg of payload, how many 250 L drums of water can it take?" a lot easier. Also, most people can do the following equation without thinking too hard: 2.67 mm + 22.798 mm + 8.3375 mm. However, given 0.54 in + 0.75 in + 0.31 in they're going to spend a lot more time and are more likely to get it wrong (instead of just doing addition, you have to convert all the fractions to have a denominator of 32 first, and most calculators will give you back a decimal inch instead of a fractional inch which isn't going to work if your ruler is fractional).