The geometric mean radius factor depends on the construction of the conductor, the number of stranded wires and the compaction of the strand.

The IEC 60287-1-3 Ed.1.0 Table 1 lists values factor K

Symbol
$K_{\mathrm{GMR}}$
Unit
-
Related
$n_{\mathrm{cw}}$
Used in
$GMR$
Choices
Number of wiresfactor K
10.779
30.678
60.714
70.726
120.739
150.747
180.755
190.758
300.764
340.766
350.767
370.768
470.77
530.771
580.772
610.772
910.774
1270.776
1690.777
2170.778
2710.779