Even with an increasing interest in scaling-up Microbial Electrochemical Technologies (MET), it is still common to focus on their "fundamentals". An important example is the production of current density (j(max)) by microbial anodes in a three-electrode arrangement (3 EA) configuration, e.g.: a graphite plate of well-defined projected (or geometric) surface area (PSA) and a cathode, both parallel to each other. With such type of anode within a 3 EA configuration, j(max)'s calculation is expected to be straightforward. Nonetheless, certain issues prevail. Occasionally, j(max) is wrongly overestimated neglecting the surface of the anode that does not directly face the cathode. Here, grown biofilms of the novel electroactive bacterium Geoalkalibacter subterraneus showed that the actual area of anode that contributes to j(max) is the total PSA (or apparent geometric area) immersed in the electrolyte available to form a biofilm regardless the side of the anode that faced or opposed the cathode even in a medium with low conductivity such as urban wastewater, a niche of application for METs. For the sake of normalization, researchers (and especially a "freshman" microbial electrochemist) are encouraged to: A) use the total PSA (or apparent geometric area) immersed in the electrolyte to calculate j(max) or B) to cover edges and faces hidden of the anode with an electrical insulator to allow the flow of current on the side of the anode that directly faces the cathode prior calculation of j(max). This normalization can be conducted when the main goal is to quantify (and thus properly report) j(max) produced when using (e.g.): a novel i) electroactive bacterium, ii) electrode material or iii) reactor design. (C) 2017 Elsevier Ltd. All rights reserved.