The magnetization loss of MgB2 wire was investigated using numerical calculations based on the finite element method. Various superconducting properties of MgB2 wire such as nonlinearity and the field dependence of the critical current were considered in the numerical formulation. An analysis of magnetization loss was carried out as a function of the external magnetic field for a wide range of operating temperatures. The numerical results were compared with conventional theories and were found to be in relatively good agreement. An alternate approach based on a normalization method using critical current data was also employed as a simple method for predicting magnetization loss. The effectiveness of the simple equation for predicting loss was verified by comparisons of both values for various temperatures.