In this work, an in-house computational code capable of simulating highly coupled physicochemical phenomena occurring in ammonia/urea SCR (selective catalytic reduction) was developed. On the basis of this computational code, the kinetic parameters of catalytic reactions were newly calibrated using the experimental results obtained over a commercial ammonia/urea SCR washcoated Fe-ion-exchanged zeolite-based catalyst. Powder-phase NH(3) TPD (temperature-programmed desorption) experiments were performed to Calibrate the kinetic parameters of NH(3) adsorption and desorption, and core-out monolith experiments were conducted to estimate the kinetic parameters of various deNO(x) reactions as well as NH(3) oxidation. The currently established SCR Model and kinetic parameters gave a good prediction for both steady-state and transient experimental results for a wide range of operating conditions. The main objectives of this study were to develop numerical tools and their implementation methodologies that: can be cost-effectively applied to the design and development of real-world ammonia/urea SCR systems. Details of the procedures and techniques in numerical modeling and kinetic parameter calibration are described step-by-step in this article.