In this study, the parasitic resistance components of lateral nanowire field effect transistors (NWFET) are modeled and extracted using technology computer aided design (TCAD) simulation. To verify the extraction result, the equation of the Berkeley Short-channel IGFET Model for the class of Common Multi-Gate (BSIM-CMG) FETs is also applied. With the development of contact resistivity, the dominant component determining overall resistance is changed from the contact resistance to the diameter of the nanowire. Considering the effective on-current, we proposed a reasonable diameter of the nanowire for sub 5-nm node gate-all-around (GAA) nanowire FET.