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Physical Measurement Laboratory

Office of Weights and Measures

NIST OWM establishes uniformity, equity, SI use, and traceability in weights and measures by advancing national and international legal metrology standards, procedures, capabilities, and training.

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2024 Info Hours Recordings Now Available
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New OWM Contacts System is Open for Business
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DYK: NIST OWM Fun Facts
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OWM Publications
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2024-2025 OWM Training and Events
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OWM e-Learning Resources

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. 

OWM's programs work to ensure:

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

To learn more about OWM and its roles and responsibilities, see About Us.

Projects and Programs

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Coriolis Mass Flow Meters as Field Test Standards

Ongoing
Customers and businesses alike rely on metering systems to monitor and deliver their liquid-based commercial products (including a range of gas and fuels) consistently over time and across a range of locations. Weights and measures officials use several well-acknowledged field test standards to
Info Hours presented by the NIST Office of Weights and Measures

Info Hours Presented by NIST OWM

Ongoing
Below are the 2024 Info Hour topics together with a recording of each Info Hour session. Manual Weight Entries An informal discussion on NIST Handbook 44 Scales Code paragraphs S.1.12. Manual Weight Entries and UR.3.9. Use of Manual Weight Entries including the history of these paragraphs and how to
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National Metrology Systems: A Framework for Global Trade

Completed
The OIML D1 "National metrology systems - Developing the institutional and legislative framework" is just that legislative framework designed to promote sound legal metrology infrastructure and build a modern (and thriving) economy. OWM’s Ralph Richter played a key role in developing the current

Blogs

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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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89 Fundamentals of Metrology

Mon, Jan 27 - Fri, Jan 31 2025
Course Description The 5-day Fundamentals of Metrology seminar is an intensive course that introduces participants to
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88 Volume Metrology Seminar

Mon, Feb 3 - Fri, Feb 7 2025
Course Description The 5-day OWM Volume Metrology Seminar is designed to enable metrologists to apply fundamental
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86 Metric System Education Resources

Thu, Feb 13 2025, 5:00 - 6:30pm EST
The International System of Units (SI), commonly known as the metric system, is easy to use and learn when taught using

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