AbstractSome numerical and analytical methods used to estimate the internal electric fields and current densities produced within human and animal models by low‐frequency electric and magnetic fields are surveyed. A major goal of such modeling is the design of laboratory experiments on cellular systems or animal models to produce a dosage comparable to that experienced by humans in a particular situation. Specific comparisons are made between the results of ellipsoidal approximations and finite‐difference methods applied to irregularly‐shaped, homogeneous, human and rat models for applied 60 Hz electric (10 kV/m) and magnetic (10−4T) fields. For scaling purposes, the induced current densities in various parts of the body are compared for rat and human models for both types of field. In addition, the current density distribution induced in rectangular culture dishes by applied magnetic fields is also described. The extension of these methods to inhomogeneous models and localized sources may not be simple. 1992 Wiley‐