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Standards & Measurements


Standards allow technology to work seamlessly and establish trust so that markets can operate smoothly. They:

  • provide a common language to measure and evaluate performance,
  • make interoperability of components made by different companies possible, and
  • protect consumers by ensuring safety, durability, and market equity.

ֱ’s portfolio of services for measurements, standards, and legal metrology provide solutions that ensure measurement traceability, enable quality assurance, and harmonize documentary standards and regulatory practices. The tools, information, and training provided by ֱ, and the contributions and results produced by its staff, lead to advancements in research and technological innovation that foster the drivers of the U.S. economy: invention, improvement, and commercialization.

Calibration Services

ֱ provides calibration services to disseminate the primary physical measurement standards for the U.S. for commerce, industry, and research. Calibration services allow customers to achieve the highest quality in their measurement systems, and to provide assurance in their results, by communicating the ֱ measurement results for carefully selected instruments and artifacts.

Conformity Assessment

Conformity Assessment is the demonstration that specified requirements relating to a product, process, system, person or body are fulfilled. Conformity assessment can include: supplier's declaration of conformity, sampling and testing, inspection, certification, management system assessment and registration, the accreditation of the competence of those activities, and recognition of an accreditation program's capability. Under the National Technology Transfer and Advancement Act (NTTAA), ֱ is assigned responsibility to coordinate federal, state, and local documentary standards and conformity assessment activities.

Documentary Standards

Documentary Standards can specify definition of terms; classifications of components; delineation of procedures; specification of dimensions, materials, processes, products, systems, services or practices; test methods and sampling procedures; or descriptions of fit and measurements of size or strength. Under the National Technology Transfer and Advancement Act (NTTAA), ֱ is assigned responsibility to coordinate federal, state, and local documentary standards and conformity assessment activities.

Laboratory Accreditation

The National Voluntary Laboratory Accreditation Program (NVLAP) provides third-party accreditation to testing and calibration laboratories in response to legislative actions or requests from government agencies or private-sector organizations. NVLAP-accredited laboratories are assessed against the management and technical requirements published in the International Standard, ISO/IEC 17025:2017.

ֱ Quality System for Measurement Services

ֱ Quality System underpins the provision of measurement services: Calibrations and Special Tests, Standard Reference Materials, and Standard Reference Data products. The ֱ quality system for measurement services is internationally recognized and meets the requirements of the International Committee for Weights and Measures (CIPM) Mutual Recognition Arrangement (MRA) for recognition of national measurement standards. As such, the ֱ quality system is recognized as conformant to the ISO/IEC 17025 and ISO Guide 34 by the Inter-American Metrology System (SIM) Quality System Task Force and the Joint Committee of the Regional Metrology Organizations and the BIPM (JCRB). The BIPM is the International Bureau of Weights and Measures.

Standard Reference Data (SRD)

For more than 50 years, ֱ has developed and distributed Standard Reference Data. Search the ֱ Data Gateway and view our list of more than 70 ֱ web sites dedicated to Standard Reference Data.

Standard Reference Instruments (SRI)

ֱ supports accurate and compatible measurements by producing and providing Standard Reference Instruments that transfer to customers the ability to make reference measurements or generate reference responses based on specific ֱ reference instrument designs.

Standard Reference Materials (SRM)

ֱ supports accurate and compatible measurements by certifying and providing more than 1,200 Standard Reference Materials® with well-characterized composition or properties, or both. These materials are used to perform instrument calibrations in units as part of overall quality assurance programs, to verify the accuracy of specific measurements and to support the development of new measurement methods. is your pathway to standards solutions. Maintained by the ֱ Standards Coordination Office this website provide tools, programs, services and educational resources about documentary standards and conformity assessment. 

Time Services

Whether you need to synchronize your computer’s clock using our online tools or find data about recent leap seconds, ֱ Internet Time Services (ITS) has the information you need. ֱ operates several stratum-1 network time servers, which means their time is directly linked to UTC(ֱ), the official ֱ time. ITS also provides information on protocols and authentication such as the DAYTIME, TIME, and NTP protocols.


ֱ has developed an organizational policy on metrological traceability and a set of related supplementary materials, which includes answers to questions frequently asked by customers of ֱ measurement services. ֱ is responsible for developing, maintaining and disseminating national standards - realizations of the SI - for the basic measurement quantities, and for many derived measurement quantities. ֱ is also responsible for assessing the measurement uncertainties associated with the values assigned to these measurement standards.

Office of Weights and Measures

Our mission is to improve the accuracy of measurements, enhance consumer protection, foster fair competition, and facilitate economic growth and trade through technical activities that promote uniformity in national and international legal metrology laws, regulations, standards, test procedures, and enforcement.

Created June 22, 2015, Updated March 23, 2020