Accurate simulations of Neutral Beam Injection (NBI) in tokamak plasmas are vitally important for the analysis of present experiments since NBI is a main heating and current drive tool used in many tokamaks. Different numerical techniques including Monte-Carlo (MC) simulations of beam particles and the solution of the Fokker-Planck (FP) equation for the beam particle distribution function are used in different codes. Although the full two-dimensional MC simulations include detailed particle physics, they are computationally expensive while the procedure based on the solution of 1D FP equation is fast and frequently used in transport codes for the modelling of tokamak scenarios. Here the NBI modules based on the MC technique (NUBEAM module routinely used in TRANSP code) and FP technique (NBI module originally included in ASTRA code) are compared for a number of JET discharges with different confinement properties.