With the increasing demand for low-power electronics, nanomagnetic devices have emerged as strong potential candidates to complement present day transistor technology. A variety of novel switching effects such as spin torque and giant spin Hall offer scalable ways to manipulate nanosized magnets. However, the low intrinsic energy cost of switching spins is often compromised by the energy consumed in the overhead circuitry in creating the necessary switching fields. Scaling brings in added concerns such as the ability to distinguish states (readability) and to write information without spontaneous backflips (reliability). A viable device must ultimately navigate a complex multi-dimensional material and design space defined by volume, energy budget, speed, and a target read–write–retention error. In this paper, we review the major challenges facing nanomagnetic devices and present a multiscale computational framework to explore possible innovations at different levels (material, device, or circuit), along with a holistic understanding of their overall energy delay–reliability trade-off.