Abstract: The specification discloses a navigational charting and calculating device comprising a base plate having a circular recess in its top side for rotatably supporting a disc therein. The disc comprises a transparent circular member having a top marking surface, and a circular base adapted to removably support the transparent circular member for holding and securing a map therebetween. The peripheral edge of the transparent circular member is graduated in degrees from 0.degree. to 360.degree.. Sliding means having at least one straight edge is supported above the disc for sliding movement across the disc in a direction perpendicular to the length of its straight edge. The straight edge has equally spaced marks along its length representative of distance. In use, the disc is rotated to align the desired direction of travel in degrees with a reference point provided on the base plate and distance of travel in the desired direction is charted with the aid of the straight edge.