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Office of Weights and Measures

The Office promotes uniformity, equity, and SI use and traceability in weights and measures by advancing national and international legal metrology standards, test procedures, capabilities, and training.

The NIST Office of Weights and Measures (OWM) provides documentary standards and services for legal metrology – the practice and process of applying regulatory structure and laws enforcement to metrology. This is directly aligned with our activities as the National Metrology Institute (NMI) for the U.S. to advance measurement science, standards, and technology and promote equitable standards worldwide, as well as our NIST mission to promote U.S. innovation and industrial competitiveness to enhance economic security.

Nearly 50 percent of the U.S. Gross Domestic Product is impacted by the sales of products and services based on weights or measures. Our staff works with a range of industry sectors -- such as the retail food sales, petroleum and chemical products, and transportation, including emerging commercial market sectors such as charging of electric vehicles and e-commerce. We promote SI use and traceability, promote and deliver documentary standards, develop technical guidance for legal metrology, and provide training for laboratory metrologists and weights and measures officials.

OWM Programs aim to ensure consumers get what they pay for, and sellers get fair payment for the goods and services they sell based on weight or measure through a uniform measurement infrastructure. This, in turn, promotes consumer confidence and helps ensure fair competition spanning local business operations to commerce on a global scale. Join OWM in celebrating Weights and Measures Week from March 1 to 7.

Originally established in 1836 as the “Office of Construction of Standard Weights and Measures”, OWM also remains the oldest office at NIST. For more information, see A Brief History of OWM.

News and Updates

SI Prefix Progress

In December 2022, the BIPM SI Brochure (9th Edition, December 2022, V2.01) was published to include the four new International System of Units (SI) prefixes

Projects and Programs


5826 Fundamentals of Metrology

Mon, Jan 30 - Fri, Feb 3 2023
The 5-day Fundamentals of Metrology seminar is an intensive course that introduces participants to the concepts of

5827 Mass Metrology Seminar

Mon, Feb 6 - Fri, Feb 17 2023
The Mass Metrology Seminar is a two-week, "hands-on" seminar. It incorporates approximately 30 percent lectures and 70



General Inquiries:

Training Inquiries

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OWM Publications Inquiries