Assessment of the limits of stability of tokamak plasmas is key to operation in high fusion performance ranges without disruption of the plasma current. Projected equilibria have been generated for the MAST-U spherical tokamak experiment, an upgrade of the previous MAST device, in order to prepare for operation. These equilibria are scanned in pressure and current profiles, and assessed with the DCON and MARS-F ideal stability codes to find the so-called “no-wall” beta limit, above which resistive wall mode instabilities can be expected in the absence of other stabilizing effects. The no-wall limit was generally found to decrease as edge safety factor q95 increased, and to slightly increase as plasma internal inductance increased. The equilibria are also assessed for the “with-wall” limit, theoretically the highest achievable performance point, again with the MARS-F code, including an approximate axisymmetric wall, and with the VALEN code which includes a 3D model of the surrounding conducting structure. Similar limits were found, despite the difference between the codes in the treatment of the wall. A significant gap between the approximate no-wall limits of βN/li = 6.44 and 7.13, found from DCON and MARS-F respectively, and the with-wall limits of βN/li = 8.68 and 8.53 from VALEN and MARS-F respectively exists due to the increased stabilizing effect of the wall in MAST-U vs. MAST. Specifically, the conducting divertor plates, which were newly installed in MAST-U, are in a region of significant mode perturbation and eddy currents are driven in these structures.