Abstract: Adjustable compass for drawing on a plane an ellipse of predetermined major and minor axes including a supported guide rod having a lower pointed end and a tracing bar attached to the guide rod through a connection which can rotate about and slide parallel to the axis of the guide rod, the tracing bar having a pointed marking element located on its lower end, the respective angles between the guide rod and the tracing bar and between the inclined guide rod and the plane of the ellipse being drawn adjustable to fixed positions so that, when the tracing bar is rotated about the guide rod while maintaining the marking element in contact with the surface on which the ellipse is being drawn, the marking element draws the desired ellipse.