Full on Bottom: The Geometry of the Gaping Top
Full-on-bottom is the most common fullness placement there is (volume settled below the apex, upper pole descending gently) and it produces the most-Googled fit complaint on earth: a cup that fits perfectly except for the empty top inch. The volume isn't missing. It's downstairs.
What full-on-bottom means
Below the apex line lives most of the volume: a straighter upper slope that curves late, a full lower pole resting on the wire. It's where soft tissue naturally settles, which makes FOB the default geometry of mature, post-nursing and higher-volume breasts, and, at every size, the reason the top of a fully-filled cup can still stand empty. The lower cup is doing all the containing; the upper cup is decoration over air.
The signature misread
The empty top inch reads as “cup too big,” the letter comes down, and now the lower cup (where your volume actually is) overfills and the wire sits on tissue, while the top still gapes. Our gaping page draws the decisive line: gaping only when you move or lean means placement (this page); gaping at rest all day means volume. FOB is the placement case, and it is overwhelmingly the more common of the two.
What actually fits
Cuts that finish where your fullness does: demi and balconette profiles whose top edge ends below the empty zone: the single biggest FOB win; stretch or lace upper panels that collapse the last inch onto the tissue; seamed cups whose lower sections are cut generous and whose upper section angles inward; and lower-cup padding used structurally: a graduated lower pad lifts settled volume up into the waiting top of the cup. Rigid full-coverage molds are the style most likely to showcase the gap.
The vocabulary around you
FOB mirrors full-on-top and rides orthogonal to projection and root width: shallow-FOB (extremely common) thrives in balconettes; projected-FOB wants its depth in the lower seam. The shape guides' relaxed and bell shapes are FOB's named cousins, and the finder there locates you precisely.
Full on bottom: answered
Is full-on-bottom normal?
It's the majority placement: gravity and time move tissue toward it, so most adults trend FOB. The gaping it causes is a construction mismatch, not a flaw in the body wearing it.
Push-up or padding for a gaping top?
A graduated lower pad (the classic push-up architecture) is genuinely the engineered solution here: it relocates settled volume upward into the empty zone. Choose it for the geometry, not the aesthetics, and the gap closes at your true size.
Will a smaller cup ever fix my top gap?
Only if the gap persists at rest all day and the lower cup is also loose: the genuine excess-volume case. If the lower cup is full, the smaller letter just relocates your problem downward while the gap stays. Placement first, letters second.
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