IEC/IEEE 62704-4:2020 describes the concepts, techniques, and limitations of the finite element method (FEM) and specifies models and procedures for verification, validation and uncertainty assessment for the FEM when used for determining the peak spatial-average specific absorption rate (psSAR) in phantoms or anatomical models. It recommends and provides guidance on the modelling of wireless communication devices, and provides benchmark data for simulating the SAR in such phantoms or models. This document does not recommend specific SAR limits because these are found elsewhere (e.g. in IEEE Std C95.1 or in the guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP)). This publication is published as an IEC/IEEE Dual Logo standard.