To determine the appropriate ring size, it is important to note that standard ring sizes increase by 0.4 millimeters for every half-size. For example, a ring with a size of 3 measures 14 mm, while a ring with a size of 3.5 measures 14.4 mm. Similarly, a ring with a size of 4 measures 14.8 mm. Typically, women’s rings range from sizes 3 (14 mm) to 9 (19 mm), while men’s rings are usually sized between 8 (18.2 mm) and 14 (23 mm).