Methods for applying first principles (FP) calculations to CALPHAD modeling, are discussed, with emphasis on easily calculated quantities that can be used to estimate input parameters for CALPHAD optimizations. Estimations of vibrational entropies, and melting points, from chemical systematics of measured elastic constants, or via semiempirical methods based on FP calculations are reviewed. Some strategies for including higher-order (clusters larger than pairs) short range order correlations in CALPHAD calculations are considered.