Dataset created for "Vanadium is an optimal element for strengthening in both fcc and bcc high-entropy alloys", to explore the effect of V in the high-entropy systems fcc Co-Cr-Fe-Mn-Ni-V and bcc Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr. Structures include pure V, misfit volumes of V in Ni, and misfit volumes of Ni2V random alloys