For the unit of acceleration, see G.


The gravitational constant, or Newtonian constant of gravitation. The constant of proportionality in Newton’s equation describing the force of attraction between two bodies. It is equal to the force of attraction due to gravity between any two bodies, times the square of the distance between their centers of mass, divided by the product of their masses.

In 1970 Taylor remarked on “the fact that a precise value of G is irrelevant for most of physics.”ยน

Source Value (× 10-11 m3·kg-1·s-2)
2010 CODATA Recommended Values of the Fundamental Constants 6.673 84;
standard uncertainty of 0.000 80
IAU (1976) System of Astronomical Constants 6.672
1986 Recommended Values of the Fundamental Constants 6.67259(85);
relative uncertainty of 128 parts per million
Mark P. Fitzgerald et al, Measurement Standards Laboratory, Lower Hutt, New Zealand. 6.6656(6)
Gabriel G. Luther et al, Los Alamos National Laboratory, New Mexico.  
Hinrich Meyer et al, University of Wuppertal, Germany. 6.6685
Winfried Michaelis et al, Physikalisch-Technische Bundesanstalt, Braunsweig, Germany. 6.71540

For the most recent authoritative value for this constant, see the elegant site of the National Institute of Science and Technology at


1. B. N. Taylor.
Report on the International Conference on Precision Measurement and Fundamental Constants.
Metrologia, vol 7, no 1, 1971.
Page 42.



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