Various Monte Carlo codes have been used for a long time in gamma ray calibration. However, to the best of our knowledge, no studies have employed the FLUKA MC code for the simulation of photon transport in an accredited calibration laboratory. This study aimed to model the benchmark of the international standard of the air kerma rate and the air kerma rates calculated by FLUKA simulation. As a comparative analysis tool, the linear regression equation used in the accredited calibration laboratory was used. After normalizing the measured and simulated values, a deviation of up to 1.0% was observed, and all the calculated air kerma rates were consistent within the uncertainty. In the analysis using the linear regression equation, the slope and interpolation uncertainty were consistent. Furthermore, the regression error was extremely small, and excellent linearity was observed. Thus, the coefficient of determination was calculated to be five or more. Since calibration sets the standard of every measurement, our study will encourage the application of FLUKA for simulations in various fields involving photons.