In a creative design process of planing craft, stepped hulls could fill a gap in the planing craft industries in response to low drag and high speed demands. However, there exists a need for new computational tools for performance prediction of such hulls. Therefore, in the current work, an attempt has been made to develop a mathematical model for performance prediction of two-stepped hulls. Savitsky's mathematical model has been modified, and in conjunction with linear wake theory, a new mathematical model has been proposed, which would enable prediction of trim, resistance and other parameters related to planing hulls with transverse steps. To validate the proposed model, existing experimental data have been used. The obtained results are in good agreement with experimental data. As such, developed mathematical model can be used in conceptual design phase of stepped hulls with transverse steps.