Weng Hong Sio and colleagues from the Materials Modelling and Design Group led by Professor Giustino have recently published papers in Physical Review Letters and Physical Review B which report a new formalism for modelling polarons. The new method combines elements of idealized mathematical models and numerical methods based on density-functional theory. A Physics viewpoint highlights that by reducing the calculations to within a single primitive crystal cell this new method opens up exciting prospects for studying more complex materials beyond the reach of previous models.