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Physical Measurement Laboratory

Office of Weights and Measures

OWM's mission is to establish uniformity, SI use, and traceability in weights and measures by advancing national and international legal metrology standards, procedures, capabilities, and training.

Weights and Measures Week
2025 National Weights and Measures Week
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Weights and Measures Support Nearly Half of U.S. GDP
OWM Info Hours 2025 sessions
Register now for the 2025 Info Hours!

The NIST Office of Weights and Measures (OWM) works to ensure that consumers get what they pay for and sellers get fair payment for the goods and services they sell by promoting a uniform and technically sound system of weights and measures. This, in turn, promotes consumer confidence and helps ensure fair competition for U.S. commerce that spans from local business operations to a global scale. 

See About OWM and OWM Fun Facts to learn more about our programs, history, and unique Responsibilities and Authorities.

OWM Quick Start: Find It Here!

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PUBLICATIONS AND DOCUMENTARY STANDARDS
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TRAINING COURSES AND EVENTS
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E-LEARNING RESOURCES
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OWM CONTACTS SYSTEM
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METRIC (SI) PROGRAM
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OWM FAQS

Projects and Programs

group photo taken at NCWM 2023 Annual Meeting; Craig VanBuren, Don Onwiler, and Mahesh Albuquerque of NCWM, Laurie Locascio and Katrice Lippa of NIST, Gene Robertson of NCWM, David Sefcik

NIST OWM – NCWM: An Enduring Partnership

Ongoing
The National Conference on Weights and Measures (NCWM) was first held as the “First Annual Meeting of Sealers of Weights and Measures of the United States” in 1905 and as part of the National Bureau of Standards (NBS), which was the predecessor non-regulatory agency to the National Institute of
OWM Laboratory Metrology Training for mass metrology

OWM Training Program: Metrology, Metrication, and More!

Ongoing
OWM offers a variety of in-person, online, and "blended" training classes and materials that provide guidance instruction on national legal metrology standards, weights and measures field inspection procedures, and laws and regulations related to packaging and labeling. OWM provides technical

Blogs

Elizabeth Gentry holding a kilogram test weight in the weights and measures training lab

Busting Myths about the Metric System

This year will be the 45th anniversary of the Metric Conversion Act, which was signed on December 23, 1975, by President Gerald R. Ford. Normally, we celebrate

Newsletter Articles and Updates

Awards

Events

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84 Mass Metrology Seminar

Mon, Mar 3 - Fri, Mar 14 2025
Course Description The Mass Metrology Seminar is a two-week, "hands-on" seminar. It incorporates approximately 30
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82 Calibration Certificate Evaluation

Thu, Apr 3 2025, 2:00 - 4:00pm EDT
This 2-hour webinar will introduce concepts necessary to successfully implement ISO/IEC 17025:2017 compliant calibration
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81 Fundamentals of Metrology

Mon, Apr 7 - Fri, Apr 11 2025
Class Description The 5-day Fundamentals of Metrology seminar is an intensive class that introduces participants to the

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