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National Legal Metrology

Promotes uniformity at the national, state, and local levels in laws, regulations, documentary standards, and practices for weighing and measuring instruments and devices to facilitate trade and protect U.S. businesses and consumers.

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Credit: NIST

About National Legal Metrology

The National Legal Metrology group within OWM serves as the primary source of technical advisors to the National Conference on Weights and Measures (NCWM) technical committees and U.S. Federal agencies, as well as conveners for U.S. National Working Groups (USNWGs) and other technical guidance activities involving U.S. Federal, State, consumer groups, and commercial industry representatives. The group also coordinates with the International Legal Metrology efforts within OWM to harmonize national and international legal metrology documentary standards and practices. The group also conducted many classes, seminars, and presentations related to the laws and regulations related to packaging, inspection and testing of commercial weighing and measuring equipment, with the goal of improving uniformity in the application of weights and measures standards and practices.

Who We Are

Staff members are legal metrologists, physical scientists and engineers, and weights and measures coordinators with experience working as weights and measures officials, weighing and measuring device type evaluators, and/or industry service specialists. 

What We Do

We collaborate with and provide technical assistance to the NCWM and its National Type Evaluation Program (NTEP), and to other Standards Developing Organizations (SDOs) to develop standards for weighing and measuring devices (aka legal metrology devices – see below), test procedures, and guidelines and interpretations, including those that are developed and published by NIST. The group also works directly with various U.S. Federal agencies, State weights and measures authorities, and a range of industry sectors to ensure uniform interpretations of labeling and net quantity laws and regulations.

The staff in this group serve as Technical Advisors to NCWM technical committees and edit, manage, and disseminate the content within NIST Handbooks 44, 130, and 133. They also serve as conveners for various USNWGs and serve as the U.S. technical points of contact or secretariats for other national and international standards developing organizations. We continually assess and respond to the needs of its customers for new weights and measures laws, regulations, documentary standards and practices. We provide training, technical assistance, and guidance to industry and weights and measures officials to ensure national uniformity of these standards and practices.

What is Legal Metrology?

Legal Metrology is the practice and process of applying regulatory structure and enforcement to metrology. Learn more here...

What is a "Legal Metrology Device"?

A "legal metrology device" refers to a weighing or measuring device that is used to determine a quantity on which a charge is based for goods or service. Learn more here…

Stakeholders and Partners

  • Commercial measuring equipment and device manufacturers
  • Commodity manufacturers, distributors, and packagers
  • Marketplace consumers and business owners
  • Standards Development Organizations (SDOs)
  • State and local weights and measures officials
  • Trade associations and advocacy groups
  • U.S. federal government agencies


5887 Fundamentals of Metrology

Mon, Jul 15 - Fri, Jul 19 2024
Course Description The 5-day Fundamentals of Metrology seminar is an intensive course that introduces participants to

5927 Fundamentals of Metrology

Mon, Jul 22 - Fri, Jul 26 2024
Course Description The 5-day Fundamentals of Metrology seminar is an intensive course that introduces participants to

Press Coverage

The Deprecation of the US Survey Foot

The American Surveyor
Some of you know about the deprecation of the U.S. survey foot already, and some may be asking “What the heck is deprecation?” So let’s start with a definition: