Based on temperature dependent photoconductivity, excitation, and emission measurements we have established the absolute location of 4f energy levels of Pr 3+ , Eu 2+ and Tb 3+ doped in LaVO 4 . In combination with an empirical model describing a systematic and material independent variation of the 4f ground states of tri- and divalent lanthanides this information was used to predict the corresponding absolute energy level positions of all the other lanthanides in the same compound. The results of our work are presented in a complete energy level diagram for LaVO 4 :Ln (Ln=La, Ce, Pr, …, Lu).