Crack width calculation in reinforced concrete is still after decades of theoretical and experimental research a controversially debated topic in the scientific, normative and practical engineering community. Nowadays, numerous design recommendations exist in the literature with sometimes very contradictory statements. One aspect is the question of additional crack width opening at the surface in bending members due to the curvature. In MC2010, MC2020 as well as in Eurocode 1992-1-1:2023 an additional opening should be regarded according to the curvature of the cracked cross section in all cases of bending, whereas EN 1992-1-1:2004 and several national annexes such as DIN EN 1992-1-1/NA2013-04 and ÖNORM B 1992-1-1:2018-01 do not require to do so. This contribution discusses the effect of additional crack width opening at the surface in bending members with special regard to member depth, crack stage and displaceable bond. As result a mechanically-sound, transparent and practicable solution will be presented and tested against experimental data.