The Disadvantages of Using the Metric System

barbol88/iStock/Getty Images

A long-standing debate in America concerns the disadvantage of using the metric system. Questions have been raised about converting to a system that uses the number 10 as a base, rather than two. Scientists who created the metric system designed it to be exact and logical; however, those who use it every day need extra information before being able to use it competently.

The Problem with Fractions

According to the British Weights and Measures Association, the metric system is based on multiples of the number 10. The BWMA states that the downside of this type of system is the number 10 can only be divided by one, two, five and 10 without resulting in a decimal or fraction. Half of 10 is five, half of five is 2.5, half of 2.5 is 1.25 and so on. Because the human brain can manage whole numbers better than fractions or long decimals, this can be difficult in every day use. The 12-month year, the 24-hour day and the 60-minute hour divide more flexibly than base 10 does.

No Natural Use

The rigidity of the metric system makes it less convenient for designing units. For example, drinking a pint or buying a two-liter bottle of soda seems natural. However, saying you would like a 400 millilitre bottle of coke does not. Similarly, a convenient unit of one foot is known around the world and makes sense to most people in terms of measuring.

Weights and Measures

According to the BWMA, weights and measures evolved out of practical experience. The imperial system was originally based on 'human' quantities, such as an inch measuring the lenght of a thumb, a foot equalling the length of one human foot and one cup of water equalling the amount of water that can be held in cupped hands. The metric system, however, was devised during the French Revolution, when the academics calculated the distance between the North Pole and the equator. They then divided this number by 10 million to get the meter. According to the BWMA, basing all units on the number 10 has made for an inflexible system. For example, with the standard system, the 12-inch foot can be easily divided in a variety of ways, whereas it is hard to divide millimetres or meters efficiently without resulting in decimals.


In engineering, drawings using the metric system would have to be in millimeters, which would result in huge, user-unfriendly numbers. For example, if you were measuring a typical sheet of plywood that was 4 feet by 8 feet in the standard system, the metric system would measure it as 1219.2 millimeters by 2438.4 millimeters. Even if these measurements were rounded up, the large numbers would still be difficult for the average human brain to visualize. Carpenters would have to work with numbers so large it would be hard to manipulate or visualize. For example, people can remember 6 feet 2 inches, or 2 pounds 4 ounces better than the metric conversions of 198 centimeters or 1,002 grams, respectively.

Most recent