Fit Problem: Cups gape or wrinkle

The short answer: Cup volume or profile is too big, or the style is too tall for a shallow or teardrop shape. Go down a cup letter, or switch to a demi or balconette cut that matches less upper fullness. Wrinkling at the bottom usually means the cup is too deep.

Gaping is empty cup: fabric that stands away at the top edge or wrinkles across the face of the cup because there is more shell than tissue. It reads like 'my cups are too big,' and sometimes that is the whole story, one letter down solves it. But gaping is also the signature symptom of a shape mismatch, which is why so many people gape in every size they try.

Shapes with less upper fullness, teardrop and slender in particular, do not fill the top third of a full-height molded cup no matter the letter. The move is not smaller volume but shorter cup: demi and balconette cuts end below the gap, and stretch-lace top panels collapse gently against whatever tissue is there. Meanwhile bottom-of-cup wrinkling points the other way, at a cup deeper than your projection, where a shallower profile like a t-shirt bra fits flush.

One more cause hides in the straps: over-tightened straps lift the cup off the body and create a top gap on a perfectly sized bra. Set straps to light contact, scoop, and re-check the gap before concluding anything about size.