Standard Article

Fundamental Constants

  1. J. L. Flowers,
  2. B. W. Petley

Published Online: 15 MAR 2011

DOI: 10.1002/3527600434.eap082.pub2

Encyclopedia of Applied Physics

Encyclopedia of Applied Physics

How to Cite

Flowers, J. L. and Petley, B. W. 2011. Fundamental Constants. Encyclopedia of Applied Physics. 33–74.

Author Information

  1. National Physical Laboratory, Teddington, Middlesex, UK

Publication History

  1. Published Online: 15 MAR 2011


We discuss the fundamental constants, considering their nature and definition as well as their experimental realization and use as measurement standards. We discuss the evaluations of the constants with emphasis on the 2006 evaluation. The proposed changes to the basis of the SI are considered as are some trends in scientific metrology.


  • fundamental constants;
  • Josephson effect;
  • quantum Hall effect;
  • least-squares adjustment;
  • CODATA adjustment;
  • quantum electrodynamics;
  • kilogram redefinition