In this article, a free distribution computational tool for academic use called DILATE is presented. The tool was developed using Microsoft Excel using Visual Basic for Applications (VBA), which facilitates the design of three-phase overhead transmission lines. DILATE integrates three principal calculation modules: electrical calculation, mechanical calculation, and tower spotting and transmission line alignment: the latter is done directly on the graphical representation of the longitudinal profile of the land, imported from a DXF file. The result is a computational tool that helps with all the processes of calculation and updating of results, reducing the time spent in the design and the possible errors that could arise from a manual procedure. The designer’s work is focused on the data input and the results analysis through its user friendly interface.