Metric System Vs. the U.S. System of Weights & Measures

The U.S. system and the metric system of weights and measures are sets of units used to quantify the size and mass of objects. The U.S. system comes from the old English system of weights and measures, while the metric system was developed to replace the English system.

History

The U.S. system was developed based on lengths of the human body going back to Roman times. The metric system was developed by France at the end of the 18th century.

Time Frame

The metric system spread slowly, but in 1875, the Convention of the Meter was held at which the metric system became the standard for all weights and measures in 17 countries. By the end of the century, more than 30 countries had changed to using the metric system.

Conversion Factors

The metric system uses a common conversion factor: 10. To go from decimeters to meters or hectograms to kilograms, you multiply by 10. The English system has a variety of conversion factors such as 16 oz. in a pound and 2,000 lbs. in a ton.

Potential

The United States is the only major country that still uses the English system. Even in the U.S., the metric system is slowly growing in use.

Fun Fact

The United States could have been the first country to adopt a metric system when Thomas Jefferson suggested it in 1790. But the United States only adopted a decimal-based currency.