A simplified model for predicting the general trends of active magnetic regenerator devices is presented. To reduce computational demands it is assumed the regenerator has sufficiently high convective interaction such that a one-phase regenerator approximation is sufficient. A corrective term is subsequently added to the thermal conductivity to account for the convective heat leak. Losses internal and external to the regenerator are also defined for a generalized AMR device. The steady state temperature span across the regenerator is then evaluated using an energy balance and real material properties with the cooling capacity, work inputs and COP post-calculated using the result. A comparison of the simplified model with experimental results was performed using single-layer and multilayer regenerators of Gd, Gd0.74Tb0.26 and Gd0.85Er0.15. The model showed good conformity in magnitude and sensitivity in all of the scenarios which varied by heat load, frequency and utilization.