Revision Standard - Active. Best practices are described for the development, validation, and application of methods for the computation and measurement of relevant metrics characterizing human exposure to electric and/or magnetic fields (collectively, electromagnetic fields) over the frequency range of 0 Hz to 300 GHz. This recommended practice is a replacement for IEEE Std C95.3-2002 and IEEE Std C95.3.1-2010, extensively revising the contents from those and harmonizing with IEEE Std C95.1-2019. Detailed methodology is not described; rather, requirements for best practice are expressed through guidance and references to other documents and standards. Examples are included to clarify the guidance. This recommended practice is intended for professional users who are familiar with basic electromagnetic field theory and practice and for persons involved in specifying or implementing critical hazard assessments or surveys such as those described in IEEE Std C95.7-2014. (The PDF of this standard is available in the IEEE GET program at no cost to you compliments of the United States Navy, United States Air Force, and United States Army https://ieeexplore.ieee.org/browse/standards/get-program/page/series?id=82)