Abstract: Molecular motors, identified in a variety of conditions ranging from biological to synthetic systems, extract work from thermal fluctuations in out-of-equilibrium conditions. Many cellular processes require molecular motors to produce motion and forces. Based on a general model of molecular motors, the generalized efficiency of a thermal Brownian motor is calculated analytically. The results obtained here are of general significance. They can be used to analyze the performance characteristics of the Brownian motors operating in the zero heat leak case.