We propose two methods to predict the AC transport current losses of ${\rm MgB}_{2}$ superconducting wires with respect to various operating currents $(I_{tr})$ and temperatures $(T)$. Firstly, the transport current loss was estimated by a numerical method (finite element analysis). In order to consider the highly nonlinear behavior of the superconducting properties according to magnetic flux density $(B)$ at each temperature, the measured $J_{c}-B-T$ characteristics were used in the calculation. The numerical results were compared with these of conventional Norris theory and showed quite good coincidence. A second method to predict the transport current loss at various temperatures, which used a loss at a specific temperature and the critical current data, is suggested. We deduce a formula for the prediction of the loss by a simple analogy through normalization, which performs excellently. The comparison of the transport current loss values calculated using the two methods is addressed.