THE UNITED STATES AND THE METRIC SYSTEM

A Capsule History

The United States is now the only industrialized The General Conference of Weights and country in the world that does not use the metric Measures, the governing body that has overall system as its predominant system of measurement. responsibility for the metric system, and which is made up of the signatory nations to the Treaty of Most Americans think that our involvement with the Meter, approved an updated version of the metric measurement is relatively new. In fact, the metric system in 1960. This modern system is United States has been increasing its use of metric called Le Système International d'Unités or the units for many years, and the pace has accelerated International System of Units, abbreviated SI. in the past three decades. In the early 1800's, the U.S. Coast and Geodetic Survey (the The United Kingdom, began a transition to the government’s surveying and map-making agency) metric system in 1965 to more fully mesh its used meter and kilogram standards brought from business and trade practices with those of the France. In 1866, Congress authorized the use of European Common Market. The conversion of the metric system in this country and supplied the United Kingdom and the Commonwealth each state with a set of standard metric weights nations to SI created a new sense of urgency and measures. regarding the use of metric units in the United States. In 1875, the United States solidified its commitment to the development of the In 1968, Congress authorized a three-year study internationally recognized metric system by of systems of measurement in the U.S., with becoming one of the original seventeen signatory particular emphasis on the feasibility of adopting nations to the Treaty of the Meter. The signing SI. The detailed U.S. Metric Study was of this international agreement concluded five conducted by the Department of Commerce. A years of meetings in which the metric system was 45-member advisory panel consulted with and reformulated, refining the accuracy of its took testimony from hundreds of consumers, standards. The Treaty of the Meter, also know as business organizations, labor groups, the “Metric Convention,@ established the manufacturers, and state and local officials. International Bureau of Weights and Measures (BIPM) in Sèvres, France, to provide standards of The final report of the study, “A Metric measurement for worldwide use. America: A Decision Whose Time Has Come,” concluded that the U.S. would eventually join the In 1893, metric standards, developed through rest of the world in the use of the metric system of international cooperation under the auspices of measurement. The study found that measurement BIPM, were adopted as the fundamental standards in the United States was already based on metric for length and mass in the United States. Our units in many areas and that it was becoming customary measurements -- the foot, pound, quart, more so every day. The majority of study etc. -- have been defined in relation to the meter participants believed that conversion to the metric and the kilogram ever since. system was in the best interests of the Nation, particularly in view of the importance of foreign trade and the increasing influence of technology in American life. The study recommended that the United States The current effort toward national metrication is implement a carefully planned transition to based on the conclusion that industrial and predominant use of the metric system over a ten- commercial productivity, mathematics and science year period. Congress passed the Metric education, and the competitiveness of American Conversion Act of 1975 “to coordinate and plan products and services in world markets, will be the increasing use of the metric system in the United enhanced by completing the change to the metric States.” The Act, however, did not require a ten- system of units. Failure to complete the change year conversion period. A process of voluntary will increasingly handicap the Nation’s industry conversion was initiated, and the U.S. Metric Board and economy. was established. The Board was charged with “devising and carrying out a broad program of planning, coordination, and public education, consistent with other national policy and interests, Questions and Answer with the aim of implementing the policy set forth in Q. What is the metric system? this Act.” The efforts of the Metric Board were largely ignored by the American public, and, in A. The metric system is a decimal-based 1981, the Board reported to Congress that it lacked system of measurement units. Units the clear Congressional mandate necessary to bring for a given quantity, such as length or about national conversion. Due to this apparent mass, are related by factors of 10. ineffectiveness, and in an effort to reduce Federal Calculations involve the simple spending, the Metric Board was disestablished in process of moving the decimal point to the fall of 1982. the right or to the left. This modern system is called Le Système The Board’s demise increased doubts about the International d'Unités or the United States’ commitment to metrication. Public International System of Units, and private sector metric transition slowed at the abbreviated SI. same time that the very reasons for the United States to adopt the metric system -- the increasing Q. Is the metric system hard to learn and competitiveness of other nations and the demands of use? global marketplaces -- made completing the conversion even more important. A. No. In everyday usage, the most common metric units are the meter (m) Congress, recognizing the necessity of the United to measure length, the second (s) to States’ conformance with international standards for measure time, the kilogram (kg) for trade, included new encouragement for U.S. mass (or weight*), the liter (L) for industrial metrication in the Omnibus Trade and volume, and the degree Celsius (EC) Competitiveness Act of 1988. This legislation for temperature. The metric system amended the Metric Conversion Act of 1975 and avoids confusing dual-use of terms, designates the metric system as the Apreferred such as the inch-pound system’s use of system of weights and measures for United States ounces to measure both weight and trade and commerce.” The legislation states that the volume. The metric system also Federal Government has a responsibility to assist avoids the use of multiple units for the industry, especially small business, as it voluntarily same quantity; for instance, the inch- converts to the metric system of measurement. pound system’s multiple units for volume include teaspoons, Federal agencies were required by this legislation, tablespoons, fluid ounces, cups, pints, with certain exceptions, to use the metric system in quarts, and gallons. their procurement, grants and other business-related activities by the end of 1992. While not mandating *In commercial and everyday use, the term “weight” metric use in the private sector, the Federal may be used as a synonym of mass. Weight is Government has sought to serve as a catalyst in the actually the force with which a body is attracted metric conversion of the country’s trade, industry, toward the earth because of gravity. and commerce. Q. Will “thinking metric” be difficult? A. Individuals, groups, and industries decide whether or not to convert and A. Not really. For example, “thinking determine conversion timetables metric” for temperature means relating according to their own needs. zero degrees Celsius (0 ˚C) with the freezing point of water, 20 degrees Q. Why should the United States convert Celsius (20 ˚C) with room temperature, to the metric system? 37 degrees Celsius (37 ˚C) with body temperature, and 100 degrees Celsius A. Since trade and communication with (100 ˚C) with the boiling points of other nations is critical to the health of water. One millimeter (1 mm) is about our economy, adopting the the thickness of a dime, and a centimeter measurement system used by 95 (1 cm) is about the width of a fingernail. percent of the world’s population is Almost everyone easily recognizes one not a matter of choice, but a matter of liter (1 L) and two liter (2 L) soda necessity for the United States. bottles. The contents of that unopened one liter soda bottle “weighs” Q. Why didn't we convert before? approximately one kilogram (1 kg). A. Support for a decimal-based Q. Who decided the United States should measuring system has existed in the convert to the metric system? United States since the 1700s. However, there was no compelling A. No one “decided the United States reason to switch because of our should go metric.” As stated in the geographical isolation and because our amended Metric Conversion Act, principal trading partner, England, did continued use of “traditional systems of not use metric units. In time the weights and measures” is still permitted United States became a dominant force “in nonbusiness activities.” However, in world trade and was able to impose metric system use has become its products, manufactured in their widespread throughout our economy. unconventional units, on other nations. Consumers may be surprised at the Times have changed. We no longer number of items in everyday use that overwhelmingly dominate world trade have been manufactured in metric units and must recognize the need to “fit” for some time. These items are accepted our goods and services into other with little difficulty and include photo- strong markets, including the graphic equipment, automobiles, European Union, the new markets of computers, pharmaceutical products, Eastern Europe, and the expanding wine and distilled spirits, and soft market of the Pacific Rim. These drinks. Also, our scientific and medical markets continually stress their communities use metric units almost preference for products and services exclusively. based on the metric system of measurement. Q. Is there a deadline for conversion? Q. What are the advantages of conversion A. No deadline has been established. for U.S. industry? Conversion in the private sector, while encouraged, is voluntary. The Omnibus A. During conversion to the metric system, Trade & Competitiveness Act of 1988 U.S. companies are able simultaneously to amended the 1975 law to make the metric streamline their operations, eliminate system the “preferred system of weights inefficiencies, and reduce their and measures for United States trade and inventories. Because products destined for commerce” and charged federal agencies both foreign and domestic markets can be with converting their activities to the designed and manufactured to the same metric system. (metric) specifications, overlapping Q. What is voluntary conversion? product lines can be eliminated. The standardization of fasteners, components, and sub-assemblies increases the efficiency established plans and internal task and productivity of all manufacturing forces for managing their change to the processes. When firms convert fully to the metric system as called for by the metric system, they are often surprised to amended Metric Conversion Act and a discover how much the conversion has 1991 Presidential Executive Order. increased their profits. “Converted” firms The General Services Administration frequently report finding new customers for has established metric specifications for their new metric products and services. products that it buys for Federal agencies. The Defense Department Q. What are the educational benefits of uses metric specifications in completing the U.S. transition to the procurement and in activities involving metric system? our allies around the world. Many new NASA projects are being designed and A. A population that is highly skilled in built to metric specifications. Most math and science is essential for national design and construction of Federal economic and social progress. By Government buildings and facilities is completing the U.S. transition to the now being done in metric units. The metric system, education and training in Commerce Department's Metric these key subjects will become much Program works with the member more efficient. Currently, huge blocks agencies of the Interagency Council on of time are spent learning the Metric Policy to identify and help cumbersome inch-pound measurements, remove barriers that may stand in the including learning to manipulate inch- way of metric conversion in federal and pound fractions and learning to make state/local rules, standards, codes, and tedious conversions between metric and regulations. inch-pound units. Much of this time can be redirected toward more worthwhile The Department of Commerce has endeavors. Opportunities for numerous started to implement several new additional curriculum improvements will outreach initiatives that seek to create surface when textbooks are revised to greater understanding and a more reflect the simpler metric system of favorable environment for national units. Training at all levels, from metrication by gaining broad-based elementary school through graduate- support from industry and the general level engineering programs, will benefit public. These initiatives include a from this important step forward. A series of information and public workforce that is truly able to “speak” awareness campaign. the metric measurement language will be better able to excel in the global Q. When should the U.S. transition be marketplace. completed?

Q. Will conversion be costly? A. Sooner is better. American remains dependent upon two systems of A. Costs will vary in different sectors of the measurement -- a situation that is economy. However, in most areas, long uneconomical, inefficient, and term benefits will be realized and should confusing. Time is of the essence more than offset any one-time because our transition to the metric conversion costs. Many industries are system is not becoming cheaper or converting as they develop new products easier. Costs and inconvenience will and as older equipment wears out. In increase dramatically for everyone as this way, conversion costs can be held to society continues to grow larger and a minimum. more complex. A short-term, nation- wide investment in metric conversion Q. What is government doing about metric will eliminate the costs of using two conversion? measurement systems and will provide the long-term return of an efficient A. All of the major Federal agencies have single-system metric economy.

For More Information Contact: Office of Weights and Measures/Metric Program National Institute of Standards and Technology 100 Bureau Drive, Stop 2000 Gaithersburg, MD 20899-2000

Phone:(301) 975-3690 FAX: (301-948-1416 Email: [email protected] URL: http://www.nist.gov/metric

NIST LC1136 October 1997 Contact info. Revised 5/2002