The calculation of volcanic deposit volume has been drastically improved from two decades because of the apparition of detailed digital elevation models. We proposed here an executable program with its graphical user interface to compute them easily. Contrary to recent calculations that assess the base of the volcano by using a contour interpolation through Delaunay triangulation and which obtain generally flat basement, we also consider the surrounding slopes to obtain the hidden volume in paleo-depression and then better assess basement topography. We also propose solutions to correct some basement elevations that are assessed above the actual topography when using recent methods. We validated the method with the Paricutin case. We also demonstrate the ability to retrieve hidden volumes covered by younger volcanoes in the case of the volcanic complex La Nieve.