  An equation has been derived to predict unit cell volume of high entropy
alloys, HEA, by two different methods. Both treatments led to the same
equation. For cubic HEA lattice parameters were calculated. The predicted
lattice parameters were compared with those reported for 68 HEAs. Lattice
parameters were also calculated using the equivalent of Vegards law for these
alloys. Average errors were 0.52, and 0.42 when Vegards law, and the equation
derived in this work were used, respectively.
