Disc mass as a function of disc radius at the time when the disc fragments. The disc radius is the radius which encompasses 95% of the disc mass. Generally speaking, a higher disc mass is required for fragmentation of more extended discs. Initial disc radii of R_init = [60, 90, 120] AU are shown by the red, green and blue points, respectively. The initial stellar masses of M_⋆ = [0.2, 0.3, 0.4]M_⊙ are denoted by the circles, triangles and squares, respectively. We note the difference between initial R_init and final disc radius R_disc (i.e. the discradius when it fragments).