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.

CODATA Recommended Values of the Fundamental Physical Constants: 2018

Published

Author(s)

Eite Tiesinga, Peter Mohr, David B. Newell, Barry Taylor

Abstract

We report the 2018 self-consistent values of constants and conversion factors of physics and chemistry recommended by the Committee on Data of the Interna- tional Science Council (CODATA). The recommended values can also be found at physics.nist.gov/constants. The values are based on a least-squares adjustment that takes into account all theoretical and experimental data available through 31 Decem- ber 2018. A discussion of the major improvements as well as inconsistencies within the data is given. The former includes a decrease in the uncertainty of the dimensionless fine- structure constant and a nearly two orders of magnitude improvement of parti- cle masses expressed in units of kg due to the transition to the revised International System of Units (SI) with an exact value for the Planck constant. Further, because the elementary charge, Boltzmann constant, and Avogadro constant also have exact values in the revised SI, many other constants are either exact or have significantly re- duced uncertainties. Inconsistencies remain for the gravitational constant and the muon magnetic- moment anomaly. The proton charge radius puzzle has been partially resolved by improved measurements of hydrogen energy levels.
Citation
Reviews of Modern Physics
Volume
93

Keywords

fundamental constants, quantumelectrodynamics, gravitational constant

Citation

Tiesinga, E. , Mohr, P. , Newell, D. and Taylor, B. (2021), CODATA Recommended Values of the Fundamental Physical Constants: 2018, Reviews of Modern Physics, [online], https://doi.org/10.1103/RevModPhys.93.025010, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=931443 (Accessed October 31, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created June 30, 2021, Updated July 7, 2021