Why the United States Retained Imperial

The United States had actually begun the process of metric adoption much earlier than most people realize. In 1790, Thomas Jefferson proposed a decimal-based measurement system for the new nation, anticipating the metric system by several years. When the French Revolutionary government sent a copper meter stick and kilogram weight to America in 1805, Jefferson and other founders seriously considered making the switch.

But historical timing worked against metric adoption. The War of 1812 disrupted trade relationships with metric-friendly European nations, while growing commerce with Britain reinforced Imperial units. More importantly, America's rapid westward expansion was happening just as the metric system was being developed. Surveyors were already laying out townships in square miles, homesteaders were claiming 160-acre plots, and railroad companies were measuring distances in miles. The infrastructure of expansion was Imperial.

The situation became more entrenched during the Industrial Revolution. American factories, built in the mid-1800s, were designed around Imperial measurements. Machine tools were calibrated in inches, pipes were sized in Imperial dimensions, and workers learned trades based on feet and pounds. Converting this vast industrial base would have required enormous investment with no immediate economic benefit.

Congress did pass the Metric Act of 1866, making metric units legal for commerce, and the United States was even a founding member of the International Bureau of Weights and Measures in 1875. But legal permission is different from practical adoption. Without government mandates or economic incentives, businesses and consumers stuck with familiar units.

The closest America came to metric conversion was during the 1970s. Rising oil prices and increased international trade made the economic costs of dual systems more apparent. The Metric Conversion Act of 1975 established the U.S. Metric Board and declared metric conversion a national policy. Television weather reports began giving temperatures in Celsius, highway signs showed distances in both miles and kilometers, and schools taught metric units alongside Imperial ones.

But the effort lacked teeth. The legislation was voluntary, and when Ronald Reagan became president in 1981, his administration dissolved the Metric Board as part of broader deregulation efforts. Without government leadership, conversion momentum collapsed. The half-hearted nature of the 1970s effort actually created more confusion, as many Americans associated metric units with government overreach rather than practical benefits.