Purpose – Calculation methods from Torenbeek, Raymer, Marckwardt, and Loftin are examined and compared. The question is whether there is a more precise method for passenger aircraft to determine the operating empty mass fraction based on new statistics. --- Methodology – Equations for estimating the operating empty mass fraction are determined from parameters including thrust-to-weight ratio, wing loading, design range, payload, and number of engines (on the wing). Only aircraft parameters are used, which are already known in preliminary sizing and for which a physical connection exist to the operating empty mass fraction. --- Findings – New methods surpass the accuracy of the classic calculation methods. This is achieved by using more and other design parameters and their optimal mathematical combination. --- Practical implications – The risk of incorrect mass estimation in preliminary sizing is reduced.