NIST works to assure that the U.S. realization of the basic and derived measurement units is consistent with the realization in other nations. NIST Laboratories engage in a number of international activities to support trade and global science, and to promote the international acceptance of U.S. measurement standards.

International Agreements and Legal Metrology

• CIPM Mutual Recognition Arrangement — National metrology institutes of the International Committee of Weights and Measures (CIPM) have signed this international arrangement calling for "mutual recognition of national measurement standards."

• Other International Agreements — Under bilateral agreements with organizations in 18 nations, NIST is working to improve the quality of the international measurement system. These complement multilateral agreements, some involving more than 20 nations.

• International Organization of Legal Metrology (OIML) — NIST serves as the U.S. representative to this 97-country treaty organization. OIML recommends performance requirements for measuring instruments, which nations may incorporate into their laws or regulations.

• Metric Program — This program helps to encourage the US transition to the metric system, the international standard for weights and measures.