Despite the availability of extensive information on Fe–Cr alloys, there have not been many recent studies toward generating high temperature calorimetry data and possible integration of these in terms of simple and physically based modeling protocols, to yield a wholesome picture of phase stability in Fe–Cr system. This study aims at partially filling this gap. In specific terms, accurate measurements of high temperature enthalpy increment (HT−H298.15) have been made on Fe–15wt.% Cr alloy using inverse drop calorimetry in the temperature range, 298–1323K. The Curie temperature and the transformation enthalpy associated with the magnetic transformation have been experimentally determined. These data are combined with relevant information available in literature for other compositions, to develop a physically based modeling approach that takes into account explicitly various contributions to the thermodynamics of αferro→αpara phase change as a function of Cr-content.