In reinforced concrete (RC) building structures, negative bending moments of secondary beams and slabs may cause the supporting edge beams to twist. In some situations, the torsional moments become critical as they lead to failure at the beam end sections near the column faces. In the current version of two modern design codes of practice, American standard ACI 318-19 and European standard EN 2004, there are some differences in the expressions quantifying the torsional capacity of RC beams that may confuse practitioners and cause them to make incorrect decision. This research aims to clarify these differences. The predictions by the codified formula are compared with each other and with the test data of two RC beams with sectional dimensions of 150 mm 250 mm loaded to complete torsional failure. Based on the comparisons, recommendations on design and detail of RC edge beams are discussed.