Skip to main content
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.

U.S. Metric Study Report

Image of covers of 345 Series, Report to the Congress A Metric America
U.S. Metric Studies, compiled for Congress by the National Bureau of Standards
Credit: NIST

In 1968, Congress authorized the Secretary of Commerce to make a study to determine the advantages and disadvantages of increased use of the metric system in the United States (Public Law 90-472).

The National Bureau of Standards (NBS, now NIST) conducted study which resulted in the Report to the Congress, A Metric America, A Decision Whose Time Has Come and 12-volume substudy reports. The Metric Study recommendations contributed to passage of the Metric Conversion Act of 1975 (15 U.S.C. 205a et seq., amended by the Omnibus Trade and Competitiveness Act of 1988).

  • NBS SP 345 (PDF). Report to the Congress. A Metric America: A decision whose time has come. Edition: July 1971.

Substudy Reports

The results of substudies of the U.S. Metric Study were published as an interim series and evaluated for the preparation of the final comprehensive report to Congress. The individual reports of the interim series are:

  • NBS SP  345-1 (PDF). International Standards. Edition: December 1970.
  • NBS SP 345-2 (PDF). Federal Government: Civilian Agencies. Edition: July 1971.
  • NBS SP 345-3 (PDF). Commercial Weights and Measures. Edition: July 1971.
  • NBS SP 345-4 (PDF). The Manufacturing Industry. Edition: July 1971.
  • NBS SP 345-5 (PDF). Non-manufacturing Businesses. Edition: July 1971.
  • NBS SP 345-6 (PDF). Education. Edition: July 1971.
  • NBS SP 345-7 (PDF). The Consumer. Edition: July 1971.
  • NBS SP 345-8 (PDF). International Trade. Edition: July 1971.
  • NBS SP 345-9 (PDF). Department of Defense. Edition: July 1971.
  • NBS SP 345-10 (PDF). A History of the Metric Controversy in the U.S. Edition: August 1971.
  • NBS SP 345-11 (PDF). Engineering Standards. Edition: July 1971.
  • NBS SP 345-12 (PDF). Testimony of Nationally Representative Groups. Edition: July 1971.




Created January 13, 2021, Updated September 22, 2023