U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Physical Measurement Laboratory

PML is a world leader in the science of measurement. We determine the definitive methods for nearly every kind of measurement employed in commerce and research, provide NIST-traceable calibrations, and disseminate standards and best practices throughout the nation. At the same time, PML works continuously at the outermost frontiers of metrology, devising tools and techniques to meet the ever-changing demands of American industry and science.

Flat, round shape in various shades of orange color, with copper wiring and other decorations covering the top third and a small, square black object surrounded by a gold frame in the center.
NIST Researchers Boost Microwave Signal Stability a Hundredfold
single-atom transistors illustration
Scientists Create New Recipe for Single-Atom Transistors

SI Redefinition

Outer circle has one wedge for each of the 7 SI units (kilogram, meter, second, ampere, kelvin, mole, and candela) and the inner circle has wedges for the 7 important constants.
Credit: BIPM

NIST is producing a series of special reports on the worldwide consensus plan to redefine four of the seven basic units of measurement in the International System of Units in terms of invariants of nature.

Explore these stories, as they become available, on the SI Redefinition Portal.

News and Updates

Events

Industry Impacts

A streaked image of a taxi and a dark car driving in Times Square, New York City street at night.

Fare Standards for Rideshare Services

To calculate fares, app-based ride services such as Lyft and Uber don’t use traditional taxi meters, but instead combine data from GPS and cellular networks to
Illustrative subset of parameterized shapes available for nanoscale photonic, electronic, mechanic, fluidic, and other applications.

Nanolithography Design Tools

Accurate production of nanoscale features on semiconductor chips is essential to their performance, but typical design tools cater to the dominance of straight
Image of a radiation pressure power meter

High-Power Lasers for Manufacturing 

Measuring the intensity of high-power lasers used by manufacturers for precision cutting and welding can be difficult due to large instrumentation challenges
atom-based magnetic sensor

Brain Mapping Technologies

Magnetic signals produced by electrical currents in the brain can be used to map brain processes and help in the diagnosis and treatment of disease

Awards

Headshot of Alexey Gorshkov

2019 PECASE - Alexey Gorshkov

The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to...
Headshot of Franklyn Quinlan

2019 PECASE - Franklyn Quinlan

The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to...
Headshot of Laura Sinclair

2019 PECASE - Laura Sinclair

The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to...
View All Awards

Press Coverage

cow illustration

Combing a Herd for Methane Emissions

American Physical Society
Specialized light beams called frequency combs could help detect greenhouse-gas emissions from livestock with greater precision than existing methods.
Mole SI Symbol Circle Graphic

A more perfect unit: the new mole

Popular Science
A video about the redefinition of the mole, featuring NIST's Savelas Rabb, Robert Vocke, and Stephan Schlamminger.

Contacts

PML Director and PML Deputy Director

Associate Director for Measurement Services and Associate Director

Executive Secretaries to Director Kushmerick and Deputy Director Williams