U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

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.

The Economic Power of Weights and Measures
The Economic Power of Weights and Measures
OWM Technical Analysis hero image
2025 OWM Technical Analysis Now Available
OWM Info Hours Announcement Banner
OWM 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!

document download icon
PUBLICATIONS AND DOCUMENTARY STANDARDS
2025 calendar icon
TRAINING COURSES AND EVENTS
icon of e-learning
E-LEARNING RESOURCES
Icon for OWM Contact System
OWM CONTACTS SYSTEM
SI wheel in black and white
METRIC (SI) PROGRAM
question mark icon
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

hand holding a cellphone showing four different apps

Legal Metrology Meets the Digital Age

The days when a telephone was just a device to make phone calls are long gone. Nowadays, almost everybody has a smartphone with the capability to use it as a
2025 C-RMAP attendees

C-RMAP 2025: “That’s A Wrap!”

In early June, over 115 metrologists from state, county, and federal government laboratories gathered with manufacturing and industry laboratory metrologists in
OWM Info Hours Announcement Banner

OWM Info Hours Update

OWM continues to host a series of Information Hours, or "Info Hours," to feature current weights and measures, laboratory metrology, or documentary standard
electric car at charging station

EVSE Metrology Trainings are a Go!

OWM is ramping up a new series of metrology training for the testing and verification of electric vehicle supply equipment (EVSE). This August, in conjunction

Awards

Events

Advanced Mass Thumbnail

2053 Advanced Mass Seminar

Mon, Jul 28 - Thu, Aug 7 2025
The 9-day, hands-on Advanced Mass calibration seminar focuses on the comprehension and application of the advanced mass
Webinar image with hands over laptop in background

75 Contract Review

Thu, Aug 14 2025, 2:00 - 4:00pm EDT
Class Description This two-hour webinar will consider internal auditing techniques and best practices used by a

Contacts

General Inquiries:

Training Inquiries

Website Inquiries:

Was this page helpful?