Why Are My Bra Cups Gaping?

Start here: three quick checks

1. Scoop and swoop. Reach into each cup and bring the tissue from under your arm forward. A cup that looked half empty often fills once everything is in it. See the scoop and swoop method.
2. Shorten the straps. Straps stretch over time. If two fingers fit under them with room to spare, tighten them and look again.
3. Look at the centre panel. Is it flat on your breastbone or lifting away? The answer separates the causes below.

If the gap is still there, work out which of these four fits.

Cause 1: the cup is too big

How to recognise it

• The gap is there along the whole top edge, on both sides.
• The cup fabric wrinkles or dents when you press it, at the bottom of the cup as well as the top.
• The centre panel lies flat and the wires sit comfortably on your ribs.
• There is spare room everywhere, not only at the top.

What to try

Go down one cup letter on the same band: 34D to 34C. If the band also feels loose, the size you want may be a band down in the same letter, such as 32D, which has a smaller cup than 34D and a firmer band.

Cause 2: the cup is the wrong shape

This is the cause most often overlooked. Cups are built for a particular distribution of tissue, and breasts with the same volume can be distributed in very different ways.

How to recognise it

• The bottom of the cup is full, or even tight, while the top stands empty.
• Going down a cup size fixes the gap but makes you spill or makes the wire dig in.
• It happens mostly in moulded, padded or T-shirt bras, and less in soft unlined ones.

What is going on

Two patterns account for most cases:

• Fuller at the bottom than the top. Many cups assume even fullness. If most of your tissue sits below the nipple, the upper section has nothing to fill it.
• Shallow shape. If your breast tissue is spread over a wide area and does not project far forward, a deep cup leaves empty space at the front or top, even though your volume matches the size.

What to try

• A balconette or half-cup. These are cut lower and more open across the top, so there is less upper cup to gape.
• A cup with stretch lace in the upper section. It moulds to you and lies flat.
• An unlined, seamed cup in place of a moulded one. Seamed cups adapt to your shape where a moulded cup holds its own.
• Avoid tall, full-coverage moulded cups if this is your pattern.

Keep your size and change the style first.

Cause 3: the cup is too small

It sounds backwards, but it is common. When a cup is too small, your breast cannot settle into it. It sits partly on top of the cup and pushes the whole bra away from your chest. The upper edge tips outward and looks like a gap.

How to recognise it

• The centre panel floats off your breastbone.
• The wires rest on breast tissue at the sides.
• You see a gap at the top edge and a bulge at the side or near the armpit at the same time.
• After a scoop and swoop the gap closes and turns into overflow.

What to try

Go up one cup letter on the same band. If the centre panel now sits flat and the gap disappears, that was the cause. The follow-on guide is spilling out of your bra cups.

Cause 4: the band or straps are not holding the cup in place

How to recognise it

• The gap comes and goes as you move.
• The band rides up at the back.
• Pressing the band down and in at the back closes the gap at the front.

What to try

A loose band lets the cups tilt forward. Move to a firmer band with the same cup volume, which is one band down and one cup up. The sister size chart shows the size. If the straps sit wide on your shoulders and pull the cup edge outwards, look for styles with straps set closer to the centre.

Which cause is it? A summary

If one side gapes and the other fits

Uneven breasts are normal, and a difference of a cup size is common. Choose the size that fits the larger side properly. Then shorten the strap on the smaller side, or use a removable insert in that cup. Bras with stretch in the upper cup are forgiving of small differences.

Frequently asked questions

Does gaping always mean the cup is too big?

No. It can mean the cup is too big, but it also happens when the cup is the wrong shape for your breasts, when the cup is too small and is being held away from your body, or when the straps are too loose. Check which before you size down.

Why does only one cup gape?

Most people have one breast larger than the other. Fit the bra to the larger side so that nothing is compressed, then tighten the strap on the smaller side or add a removable pad to that cup.

Why do T-shirt bras gape on me?

Moulded cups have a fixed shape and cannot adapt to yours. If your breasts are fuller at the bottom than the top, or shallower than the mould, the upper edge stands away. An unlined or stretch-lace cup in the same size will often fit where a moulded one does not.