Official National Institute of Standards and Technology Response to Make the Metric system the standard in the United States, instead of the Imperial system.

Supporting American Choices on Measurement

By Patrick D. Gallagher

Thanks for your petition.

There’s a lot of history here. Right after the Civil War, President Andrew Johnson signed legislation that made it "lawful throughout the United States of America to employ the weights and measures of the metric system in all contracts, dealings or court proceedings." In 1875, the United States was one of the original 17 nations to sign the Treaty of the Metre. Since the 1890s, U.S. customary units (the mile, pound, teaspoon, etc.) have all been defined in terms of their metric equivalents.

So contrary to what many people may think, the U.S. uses the metric system now to define all basic units used in commerce and trade. At the same time, if the metric system and U.S. customary system are languages of measurement, then the United States is truly a bilingual nation.

We measure distance in miles, but fiber optic cable diameter in millimeters. We weigh deli products in pounds, but medicine in milligrams. We buy gasoline by the gallon, but soda comes in liter-size bottles. We parcel property in acres, but remote sensing satellites map the Earth in square meters.

While many countries mandate the use of the metric system by law, the U.S. Congress has repeatedly passed laws that encourage voluntary adoption of the metric system. We use a mixture of metric and customary units depending on the context. We also have a long tradition of voluntary standards and our bilingual system of measurement is part of that tradition.

The Commerce Department’s National Institute of Standards and Technology (NIST), the agency I direct, was specifically tasked by Congress to help businesses and federal agencies adopt use of metric units.

The NIST Metric Program provides manufacturers and exporters with the information about the metric system they need to sell U.S. goods abroad. And it helps distribute resources for educators who are teaching the metric system in their classrooms. That responsibility is growing as more students look to careers in science, technology, engineering, and math, where metric is universal.

Since the 1970s, all American schools have taught the metric system. Many federal agencies use metric routinely, and the U.S. military does so almost exclusively. Moreover, since Congress updated the Fair Packaging and Labeling Act in 1992, most consumer products in this country are labeled in both metric and U.S. customary units. So-called dual-unit labeling has helped consumers become familiar with using metric units.

NIST is currently working to make it possible for manufacturers to label their products with metric units only (.pdf) if they choose to do so because it will reduce their costs or improve their international competitiveness.

Ultimately, the use of metric in this country is a choice and we would encourage Americans to continue to make the best choice for themselves and for the purpose at hand and to continue to learn how to move seamlessly between both systems.

In our voluntary system, it is the consumers who have the power to make this choice. So if you like, “speak” metric at home by setting your digital scales to kilograms and your thermometers to Celsius. Cook in metric with liters and grams and set your GPS to kilometers.

We were thrilled to see this petition from “We the People” succeed. Feedback like this from consumers shows everyone from policymakers to businesses how important having this choice is to Americans.

So choose to live your life in metric if you want, and thank you for signing on.

Patrick D. Gallagher is Under Secretary of Commerce for Standards and Technology and Director, National Institute of Standards and Technology

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