What is the range of input gate current of FET?

The input gate current of a Field-Effect Transistor (FET) is ideally zero because FETs are voltage-controlled devices with very high input impedance. In practice, the gate current may be in the range of picoamperes (pA) to nanoamperes (nA) due to leakage currents and other non-ideal behaviors. This exceedingly low current helps maintain the efficiency and performance of FETs in various applications.