Two people can share the same calculated size and still need very different bras. One may need deeper cups that move outward from the chest wall, while the other needs a shape that spreads volume more broadly across the frame.
Projection is about depth at the wire
Projected tissue needs enough room near the base of the cup so the wire can stay in the breast fold. If the cup is too shallow, the bra often slides downward and creates wrinkling near the bottom edge.
Shallower shapes often prefer open but not necessarily larger cups
A shallow bust may fill width and upper cup area without needing as much forward depth. In a very projected style, the fabric can collapse or gap even when the size label is technically correct.
Use fit symptoms to identify shape needs
Downward wire migration, bottom creasing, and a floating gore often suggest more projection. Empty apex space, upper-cup looseness, or wire width that feels excessive can suggest a shallower or more open style would work better.
Key takeaways
- Projection describes cup depth, not only size.
- A shallow shape can still need a larger cup, just in a different geometry.
- Shape clues are often clearer than the size label itself.
Reader note
This guide is intended for apparel fit education. Bra size labels vary by brand, and calculator results work best when paired with real fit feedback.