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Measuring Systems in the United States

Since colonialists brought with them the measuring methods of their homeland, confusing and contradictory measuring systems came to America. For instance, the imperial gallon used in England did not come to America. The U.S. gallon is a smaller one and was called the Queen Anne wine gallon by the British. Today this difference in size between the Imperial gallon and the U.S. gallon causes confusion when converting to the metric system.

The law of 1792, under the new Constitution of the United States, provided for fractional coinage and for the decimal system. The adoption of the decimal system for coins shows that the American leaders recognized the advantages of the simple decimal system. In 1795, France tried to convince the United States to use the metric system, but Congress did nothing. In 1821 John Quincy Adams wrote a comprehensive report for Congress based on a four-year investigation. His report dealt with the metric question and the modernization of our measurement system: An excerpt of the report follows:

"Weights and Measures may be ranked among the necessaries of life to every individual of human society. They enter into the economical arrangements and daily concerns of every family. They are necessary to every occupation of human industry; to the distribution and security of every species of property; to every transaction of trade and commerce; to the labors of the husbandman; to the ingenuity of the artificer; to the studies of the philosopher; to the researches of the antiquarian; to the navigation of the mariner; and the marches of the soldier; to all the exchanges of peace, and all the operations of war. The knowledge of them, as in established use, is among the first elements of education, and is often learned by those who learn nothing else, not even to read and write. This knowledge is riveted in the memory by the habitual application of it to the employments of men throughout life."

This was the first U.S. metric study. Although three decades earlier, Thomas Jefferson also had written a report for the Congress on the need for modernization of weights and measures, the metric system was no more than a conception in this time, and his report was considered only an alternative not to be entertained seriously by the newly founded United States of America.

Despite repeated requests in Congress, there was no legal length standard in the U.S. until 1832. More or less authentic copies of the British copies of the yard were used as length prototypes. In 1832, the Treasury Department decided to admit as a legal Yard the distance between the lines 27 and 63 of a certain bronze bar, 82 inches in length, bought in 1813 in England for the Federal Survey Department. When the British yard bar, which was destroyed in 1834, was replaced in 1855, a new bronze copy No. 11 was sent to the United States which became the legal American Yard Standard.

Even though progress was slow, there was an improvement in establishment of the metric standards which the entire world recognized. Like the United Kingdom, the Americans found it necessary to define their customary measurements in terms of international metric standard. Our units of length, mass and volume are all stated in terms of the metric standards.

In 1863, the United States was represented at two important international congresses convened to consider matters of weights and measure. The International statistical Congress in Berlin declared that uniformity in weights and measures was o the highest importance, particularly for international commerce. Recommendations made by the Postal Congress held at Paris resulted in the adoption of the metric system for international postal service.

Congress passed a Bill in 1866 which permitted use of the metric system of measurement in the United States. The value for the metre was given as: 1 metre = 39.37 inches or 1 yard = 0.914 401 829 metre. The metric prototype chosen was a metal bar known as the Committee Meter because it had been guaranteed to conform to the Metre des Archives by the French Committee in 1799. In 1873, metric weights were extended to silver coins. The weight of the half dollar is 12.5 grams; the quarter 6.25 grams; the nickel is 5 grams and the dime is 2.5 grams. In 1875 the United States entered a treaty with 17 other countries establishing the International Bureau of Weights and Measures. In 1890, the United States received two of the International prototype metres and two of the kilogram artifacts. One of each of these standards was adopted as the National Prototype Metre and Kilogram and as the primary standards for the United States. As such they became the fundamental standards for determining the yard and the pound. The prototype metres and kilograms are preserved at the National Bureau of Standards. In 1896, and again in 1901, bills were introduced recommending the adoption of the metric system for all weights and measures in the United States, but for one reason or another the bills failed to pass. In the years following, many bills have been introduced which recommended establishing the metric system as the legal standard of the United States, however, very little action has been taken.

In 1968, Congress asked for a three-year, sweeping investigation of the metric question because it determined that the world trend toward metric called for a new assessment. The investigation involved public hearings, supplemented by surveys on international trade, business and industry, education, national security -- almost every activity in our society -- and in 1971, the final report titled A Metric America -- A Decision Whose Time Has Come was released. It consisted of the comprehensive report plus twelve sub-study reports covering all aspects of the study.

Finally, in 1975 Congress passed the Metric Conversion Act. The major provisions of the bill provide for:

  • Adaptation of SI as predominant system of measurement units
  • No specific timetable
  • Voluntary participation
  • A Metric Board
  • Costs of Conversion
    • treat as other costs of doing business
    • no tax credits or subsidies
    • hardship cases to be reviewed by Board