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The Fundamental Physical Constants



Peter J. Mohr, Barry N. Taylor


The Committee on Data for Science and Technology (CODATA) was established in 1966 as an interdisciplinary committee of the International Council of Science (ICSU, formerly the International Council of Scientific Unions). Soon thereafter, in 1969, CODATA established the Task Group on Fundamental Constants to periodically provide the scientific and technological communities with a self-consistent set of internationally recommended values of the basic constants and conversion factors of physics and chemistry. Under the auspices of this task group, We have recently completed a new least-squares adjustment of the values of the constants termed the 1998 adjustment that takes into account all relevant data available through 31 December 1998.1 The accompanying tables give the 1998 CODATA recommended values resulting from that adjustment, with the exception of some specialized x-ray related quantities and various natural and atomic units. The complete 1998 CODATA set of more than 300 recommended values, together with a covariance matrix of some of the more widely used values and a detailed description of the data and their analysis, are given in ref. 1. All of the values and all of their covariances (in the form of correlation coefficients) are available on the Web at, in a searchable database provided by the Fundamental Constants Data Center of the NIST Physics.
Physics Today


CODATA, fine-structure constant, fundamental constants, molar gas constant, Planck constant, recommended, values of fundamental constants


Mohr, P. and Taylor, B. (2000), The Fundamental Physical Constants, Physics Today (Accessed April 16, 2024)
Created August 1, 2000, Updated February 17, 2017