Background

Welcome to the confusing system of weights and measures in America. It is a very old system that was inherited from the traditional units of weights and measures of England (Imperial system) in 1789 during the meeting of the first U.S. Congress after America gained independence from England. Now, over 200 years later, the rest of the world has officially adopted the metric system of weights and measures, which was developed in France in 1790, with America remaining as the only industrialized nation in the world to be using its original and archaic system. In fact, as of 2006, there were only three countries in the entire world that have not officially changed to the metric system. Those three countries are the United States, Liberia, and Burma. The system of weights and measures in use today in America is referred to as the U.S. customary system or the English system.

There have been a few half-hearted attempts by the U.S. Congress to move America to the metric system. Because of increased trade between America and Europe in the 1800s, Americans were increasingly forced to deal with the metric system because it was becoming the standard in Europe during that time. In 1866 the U.S. Congress passed a law that allowed the metric system to be used where needed in addition to the U.S. customary system for contractual matters of trade and commerce. Throughout the late 1800s and the 1900s the U.S. government attempted several times to encourage Americans to prefer the metric system over the U.S. customary system. Most notably was the Metric Conversion Act of 1975 that tried to move America entirely to the metric system, but only on a voluntary basis. Because most attempts by the government to move America to the metric system have been based upon a voluntary basis rather than a mandatory basis, today America is a mixture of both the metric and U.S. customary systems. The metric system is mostly used by the scientific, engineering, medical, and foreign trade professions in America but even these professionals continue to mix in parts of the U.S. customary system. The average American however continues to use only the U.S. customary system in their day-to-day life.

Foreigners coming to America will see little of the metric system in their daily lives unless they are working in a professional environment in the scientific, engineering, medical, or foreign commerce fields. The metric system of course is a decimal system or base-10 system in which larger or smaller units were created by dividing or multiplying the basic units by 10 and its powers. Instead, they will be faced with measurements of inches, feet, yards, miles, teaspoons, tablespoons, cups, ounces, pints, quarts, and gallons. None of these measurements are based in any way upon 10 or its powers.The larger or smaller units of the U.S. customary system were created by multiplying or dividing the basic units by 2, 3, 4, 12, 16, 32, 64, 128 or any other number it seems except 10 depending upon what measurement it is. Parts of the U.S. customary system were actually developed by the Romans over 2,000 years ago. You can use our conversion calculators to convert between the U.S. customary system and the metric system.

Background: You are here.
Units of Weights and Measures