Whatever Happened to the Metric System?

1. America Inherited Confusing Measures, Sparking Decimal Dreams

Decimals would form a new republican math, which would—in Jefferson’s vision—be taught to the innumerate populace by dimes and cents, thus paving the way for the next step: the decimation of all weights and measures.

Colonial chaos. The newly formed United States inherited a bewildering array of customary measures from England, complicated by local variations and the circulation of foreign coins. Keeping accounts required complex conversion tables, and simple questions like how many feet in a mile (5,280) or square feet in an acre (43,560) had non-intuitive answers. Even the definition of a pound varied depending on what was being weighed.

Jefferson's vision. Thomas Jefferson, tasked with proposing a national currency and later weights and measures, saw this chaos as an opportunity for rational reform. Inspired by Simon Stevin's work on decimal fractions, Jefferson proposed adopting the Spanish dollar but dividing it into tenths, hundredths, and thousandths – a radical decimal system no other nation had fully implemented. He believed this decimal currency would educate the public and pave the way for decimalizing all other measures.

Body vs. Decimal. While Jefferson championed the abstract logic of decimals, customary measures often had roots in human anatomy (foot, yard, fathom, cubit, inch from thumb). This anthropomorphic connection was later used by opponents of the metric system, arguing that traditional measures were more intuitive and "suited to humans," contrasting with the metric system's "rationalism" born of the Enlightenment.

2. The French Revolution Forges a Rational, Universal System

For all time, for all peoples.

Chaos in France. Pre-revolutionary France suffered from an even greater multiplicity of measures than the US, with estimates reaching 250,000 different units tied to feudal privileges and local customs. This hindered trade and administration, fueling peasant grievances against lords who manipulated measures like the bushel. Liberal reformers saw uniformity as essential for a modern, unified nation.

Enlightenment ideals. Amidst the revolutionary fervor, the French Academy of Sciences was tasked with creating a new, scientifically based system of measures. Rejecting arbitrary standards like a king's foot, they sought a standard derived from nature itself. After debating between the seconds pendulum and the earth's circumference, they chose the latter, defining the meter as one ten-millionth of the distance from the North Pole to the equator along the Paris meridian.

Decimal logic. The savants embraced decimal division for all measures (length, capacity, weight), inspired by the simplicity seen in decimal currency. They also proposed a radical nomenclature using Greek prefixes for multiples (deca-, hecto-, kilo-) and Latin prefixes for subdivisions (deci-, centi-, milli-), aiming for a precise, philosophical language of measurement distinct from old, confusing names. Despite the scientific ambition, the project was costly and slow, drawing criticism amidst the chaos of the Terror.

3. Napoleon Spreads Metric, Then Compromises with Tradition

"We have finished the romance of the Revolution," Napoleon said shortly after his consolidation of power, "we must now begin its history, only seeking for what is real and practicable in the application of its principles, and not what is speculative and hypothetical. To follow any other course at the present day would be to philosophize and not to govern."

Revolutionary spread. The metric system, along with the decimal franc and the revolutionary calendar, was part of the administrative toolkit spread by French armies across Europe during the Revolutionary and Napoleonic Wars. As France annexed territories or established sister republics and later kingdoms, the metric system was often imposed as part of a broader effort to sweep away feudal customs and institute rational, uniform governance.

Pragmatic adjustments. Facing popular resistance to the new, foreign-sounding names and decimal divisions in everyday use, Napoleon introduced the système usuel in 1812. This system retained the metric standards (meter, kilogram) but allowed the use of traditional names (livre, pied, once) and customary subdivisions (halves, quarters, twelfths, sixteenths). This was a step back from decimal purity but acknowledged the difficulty of changing ingrained habits.

Post-Napoleonic retreat. Following Napoleon's defeat, many European states reverted to their old measures as part of a general restoration of the ancien régime. The metric system survived primarily in areas with strong bureaucratic or scientific support, or where it had been deeply embedded during French rule. Its future seemed uncertain, especially as Britain developed its own standardized Imperial system.

4. The 19th Century Quest for Universal Standards

"A day will come when there will be no battlefields, but markets opening to commerce and minds opening to ideas," Hugo said.

Internationalist vision. The mid-19th century saw a surge in internationalism, fueled by technological advances like steam travel and the telegraph, and liberal ideals promoting free trade and peace. Figures like Victor Hugo envisioned a United States of Europe and eventually a unified world, where universal standards in language, currency, and measures would foster understanding and cooperation, making war obsolete.

Congress movement. International congresses on various topics (peace, statistics, law, postal services) became forums for discussing and promoting universal standards. The International Statistical Congresses, in particular, strongly advocated for the metric system and a universal decimal currency, recognizing their value for data comparison and trade. These gatherings created networks of like-minded reformers across national borders.

Metric momentum. Despite earlier setbacks, the metric system gained renewed momentum in Europe, particularly after France officially restored the pure decimal system in 1840. Countries like Belgium, Switzerland, Italy (during unification), and eventually Germany adopted it, often seeing it as a symbol of modernity and a practical tool for trade. The 1851 Great Exhibition in London and the 1855 Exposition Universelle in Paris showcased the metric system and spurred the formation of international pro-metric organizations.

5. Opposition Rises, Rooted in Tradition, Religion, and Nationalism

Perhaps when your culture is taken from you piece by piece, you don’t care until it is too late.

Cultural resistance. While proponents saw the metric system as rational and universal, opponents viewed it as an artificial imposition that disregarded history and tradition. Figures like Charles Piazzi Smyth, the Astronomer Royal of Scotland, championed the "pyramid inch," arguing that Anglo-Saxon measures were divinely ordained and embedded in the Great Pyramid, making them superior to the "atheistic" metric system born of the French Revolution.

Practical concerns. Beyond philosophical objections, practical arguments against metric adoption included the immense cost and disruption of converting tools, machinery, and everyday habits. Critics argued that the metric system's decimal nature, while good for scientists, was less intuitive for common tasks like dividing goods (e.g., pizzas cut into halves or quarters, not tenths). The complexity of the prefix system also caused confusion.

National identity. For some, particularly in Britain and the US, resisting the metric system became tied to national identity and a rejection of European, specifically French, influence. The idea of abandoning familiar measures for a foreign system was seen as a surrender of sovereignty and cultural heritage, especially as the metric system spread alongside French legal codes and political influence in the 19th century.

6. The US Debates Metric Repeatedly, Adopting Time Zones but Not the Meter

"America has never lost a war but never won a conference," Will Rogers quipped, but America won this one, so far as there was winning to be had.

Early attempts fail. Despite Jefferson's early advocacy and subsequent reports like John Quincy Adams's comprehensive study in 1821, the US Congress repeatedly failed to adopt a national system of weights and measures. Adams, while admiring the metric system, ultimately recommended inaction, prioritizing uniformity with Britain over adopting the metric system, which he felt was still too uncertain in its future.

Standard Time success. While metric adoption stalled, the US successfully implemented Standard Time in 1883, a reform driven by the chaos of multiple railroad times. Figures like Cleveland Abbe and Sandford Fleming championed the idea of time zones linked to a prime meridian. The International Meridian Conference in Washington in 1884, where the US played a key role, ultimately adopted Greenwich as the world's prime meridian, a significant step towards global time uniformity.

Metric push continues. Pro-metric advocates, organized in groups like the American Metrological Society, continued to lobby Congress, arguing for the meter's inevitability and its benefits for science, education, and trade. They achieved minor victories, such as the legalization of the metric system in 1866 and the adoption of metric dimensions for the nickel coin. However, strong opposition from industry and traditionalists, coupled with a lack of sustained political will, prevented full adoption.

7. Metric Becomes a Global Toolkit for Modern Nations

Ditching the archaic standards of an overlord was also the thinking of the duchy of Finland when it exchanged the ruble for the markka, which it set to equal one gold franc.

Symbol of modernity. As empires crumbled and new nations emerged in the late 19th and early 20th centuries, particularly after the World Wars, many adopted the metric system and decimal currencies (often based on the franc) as part of their transition to modern, independent states. These standards were seen as a toolkit for rational administration, international trade, and shedding the legacy of former overlords or medieval systems.

Global spread. The metric system spread across Europe, Asia (Japan, China, Turkey), and Latin America, often through government mandates. While implementation could be slow and met with local resistance (like Brazil's Quebra-Quilo revolt), the trend towards metric became undeniable. The international gold standard, though ultimately unstable, also saw widespread adoption, facilitating global trade with fixed exchange rates.

Other reforms. The push for universal standards extended beyond measures and currency. The Gregorian calendar, despite its flaws, became the de facto global civil calendar. Efforts were also made towards universal time (Standard Time zones, 24-hour clock) and even universal language (Esperanto), reflecting a broader internationalist desire for global uniformity and cooperation.

8. The 1970s US Metric Push Collides with Public Backlash

"The distress that you are intending to cram down the throats of the American people should be considered treason."

Renewed momentum. Following World War II, and particularly spurred by the Sputnik launch and concerns about US competitiveness, interest in metrication revived in America. A comprehensive government study, "A Metric America: A Decision Whose Time Has Come" (1971), strongly recommended conversion, arguing it was inevitable and economically beneficial. Major US corporations began transitioning, and dual labeling appeared on products.

Voluntary approach. The Metric Conversion Act of 1975 established a national policy to plan and coordinate increased metric use but did not mandate conversion or set deadlines. A US Metric Board was created to facilitate this voluntary transition. However, many advocates and the public initially perceived the act as a commitment to mandatory conversion.

Public resistance. As metric signs appeared on highways and metric units were introduced in schools and some products, public opposition intensified dramatically. Fueled by concerns about cost, confusion, and a sense of imposed change, groups like "We Ain't Metric" gained traction. The backlash, particularly against metric highway signs, demonstrated strong popular attachment to customary measures and ultimately undermined the voluntary conversion effort, leading to the abolition of the Metric Board in 1982.

9. Technology Enables a Dual-Measurement World, Making Metric Optional

Why would Americans go metric when computers have done the job for them and they don’t even have to know about it?

Containerization's impact. The rise of container shipping revolutionized global trade, making the physical act of measuring bulk goods less visible and reducing the importance of traditional port measures. Ironically, this US innovation, initially based on customary feet (the TEU), facilitated global commerce without requiring universal metric adoption at the consumer level.

Computing power. The advent of computers and digital technology made converting between measurement systems instantaneous and seamless. Software could handle conversions in the background, allowing industries and individuals to use different units without significant friction. This technological capability undermined a key argument for mandatory metrication – that it was necessary to avoid errors and facilitate calculations.

Dual system reality. The US has evolved into a bimensural nation, where metric units are used extensively in science, manufacturing, and international trade, while customary units persist in everyday life, retail, and certain industries. This dual system, facilitated by technology, allows Americans to benefit from metric where useful without abandoning familiar measures. The cultural value and historical connection of customary units remain, while the need for a single, universal system for all purposes has diminished in the digital age.

Last updated: June 22, 2025