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U.S. Metrication

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What is Metrication? | Best Practices | Costs and Benefits | Case Studies |
Errors and Mishaps | Metrication in Law | Education | Training | Metrication Resources for Researchers

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What is Metrication?

Metrication is a term describing a shift from the use of customary measurement units to the International System of Units (SI), commonly known as the metric system. Operating with only one measurement system is ideal. Historically, two major approaches have been used to implement changes: top down (mandatory) or marketplace driven (voluntary). When using a top-down approach, costs expended by an organization occur upfront and benefits are timely. A marketplace approach minimizes upfront costs by absorbing them into normal operations and budgets. The long-term process comes with a major risk: working concurrently with multiple measurement systems can lead to errors and inefficiencies. Explore the Metrication FAQs for more information.

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Best Practices

Organizations know their business model and are positioned to make the best decision for their operations. For organizations systematically adopting the SI within their business systems, these practices have been identified to ease transitions and reduce costs. Learn more…

Costs and Benefits

Use of the SI facilitates trade and business internationally and spurs economic growth. U.S. trading partners primarily use the metric system in trade and commerce. Organizations involved in both domestic and foreign activities find using the SI advantageous. Industries that adopt SI infrastructure and best practices benefit from improved interoperability of materials and product efficiency. The inability to produce products, communicate information, or provide services in SI units could disadvantage a business operating internationally because of the prevalent use of these measures. Learn more…

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Case Studies

U.S. industry sectors are moving toward increased SI use at different tempos. Manufacturers that rely on international supply chains are at the high end of the Metric Continuum. Multiple case studies have been published across multiple industries. Most studies were conducted between 1970 to 1980 during early national metrication discussions. Since this time, companies have continued to internally metricate without publishing the costs or the achieved benefits. Learn more...

Errors and Mishaps

Because metrication is not required in the United States, many businesses operate in both SI and U.S. customary units. Simultaneously using two measurement systems, however, often causes unit errors; in some cases, these errors are extraordinarily costly, while others have caused fatalities. Some of these disastrous errors have been formally investigated and published. Learn more...

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Metrication in Law

Congress has established a national policy to make the metric system the preferred system of measurement for trade and commerce in the United States. Resources for federal and state agencies seeking to increase metric usage in government programs are readily available. Learn more...


SI knowledge, skills, and abilities are critical education elements for measurement science and other Science, Technology, Engineering, and Mathematics (STEM) careers. Working in a hybrid or dual measurement system environment has a particularly significant impact on the U.S. education sector. Teaching two measurement systems causes notable inefficiencies. NIST recommends 10 methods for teachers to effectively implement SI education into the classroom. Learn more...

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SI knowledge and fluency in metric measurements are valuable workforce skill sets which can set personnel apart from others that do not have metric measurement experience. Examining strategies for implementing metric training within an organization will enable a smooth transition. Learn more…

Metrication Resources for Researchers

Organizations and others interested in discovering more about metrication are invited to explore a curated list of publications and related resources. Learn more…

Disclaimer: Any mention of commercial products within NIST web pages is for information only; it does not imply recommendation or endorsement by NIST.

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Created July 13, 2022, Updated September 28, 2023