38C

38C is a bra size that combines a band measurement of approximately 38 inches with a C cup. It is used in many Western sizing systems, particularly the United States, and is commonly found in other markets that adopt similar cup-letter conventions. The cup letter indicates the volume difference between the bust and the underbust, with a C cup typically reflecting about a 3-inch difference, although actual cup volume can vary by brand, style, and fabric.

To determine whether 38C is a proper fit, you measure around the ribcage directly under the breasts for the band size, and around the fullest part of the bust for the bust size. The difference between these two measurements corresponds to the cup size: roughly 1 inch for A, 2 inches for B, 3 inches for C, and so on. In practice, differences in construction and padding mean that the same difference can feel different across brands. As a result, fit can vary and trying bras on or using brand-specific size charts is often necessary.

Sister sizes provide alternative options with the same cup volume but different band sizes. For example, 38C has sister sizes 36D and 40B in common US sizing systems. Some people find a different sister size provides a more comfortable fit, even if the cup volume is similar.

Regional variations exist: European and other markets may use centimeter-based bands (for example, 85C or 90C) that approximate the same cup volume as US 38C, but exact fit depends on the brand.