B‑Cup Bras: Sizing, Fit, and What to Expect

A B cup indicates a 2‑inch (≈5 cm) difference between the bust measurement (fullest part) and the underbust (band) measurement. It is often considered “average,” but fit varies widely by brand, style, and individual breast shape.

Key Fit Points

• The band should be snug on the loosest hook, providing 80–90% of support.
• Cups must fully contain breast tissue without spillage or gaping.
• Straps should stay in place without digging.
• Center gore should lie flat against the sternum.

Professional fitting is recommended because sizing is not standardized across manufacturers.