Tunnel Field Effect Transistor can be introduced as an emerging alternate to MOSFET which is energy efficient and can be used in low power applications. Due to the challenge involved in integration of band to band tunneling generation rate, the existing drain current models are inaccurate. A compact analytical model for simple tunnel FET and pnpn tunnel FET is proposed which is highly accurate. The numerical integration of tunneling generation rate in the tunneling region is performed using Simpson’s rule. Integration is done using both Simpson’s 1/3 rule and 3/8 rule and the models are validated against numerical device simulations. The models are compared with existing models and it is observed that the proposed models show excellent agreement with device simulations in the entire region of operation with Simpson’s 3/8 rule exhibiting the maximum accuracy.