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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.

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

Making the DNA Melt Curve More Accurate

DNA is not only the blueprint of life; it has become the backbone for making tiny structures that can be inserted into the human body to diagnose and treat

Events

Industry Impacts

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

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

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

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

Press Coverage

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.

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