AA Cup Size Guide

AA cup measurements

AA is labelled the same in UK, US and Australian sizing. European sizing also uses AA.

AA or A? Check the band first

Many people wearing an AA are in a band that is too big. Cup letters are relative to the band, so a loose band produces a smaller letter. Someone in a 34AA with a 30-inch ribcage is closer to a 30B: the same small volume on a band that fits.

Measure your underbust. If it is two or more inches smaller than the band you wear, try the smaller band with a larger letter. A firm band often removes the gaping that seemed to be a cup problem. The calculator will give you the size.

Why AA cups gape, and how to stop it

Gaping at the top of the cup is the commonest complaint at this size. The cause is nearly always shape. A moulded cup is a fixed dome, and a small breast is usually wider and flatter than the dome.

• Choose soft cups over moulded ones. Unlined fabric lies against you. Foam stands away.
• Choose lower-cut cups. A half-cup or balconette shape has less upper cup to gape. Triangle cups work well too.
• Avoid cups with a lot of depth. Look for words such as "shallow", "petite" or "small bust" in the description.
• If you like padding, a graduated push-up pad at the bottom of the cup fills the space where a uniformly thick pad leaves a gap.

The other causes of gaping are covered in why your bra cups are gaping.

Styles that suit an AA cup

• Bralettes and triangle bras. With little weight to support, soft unstructured styles are comfortable and fit closely.
• Non-wired T-shirt bras made of thin, flexible foam, where you want a smooth line.
• Crop tops and soft sports bras, which double as everyday wear.
• Wired bras are fine if you like them. Check that the wire is not wider than your breast, which is common in small cups on larger bands.

Where to buy AA cups

Mainstream ranges often start at an A cup, so AA takes a little more looking. The large high-street chains carry AA in some core styles, usually in 32 to 36 bands, and Primark's extended range begins at 28AA. Teen and first-bra ranges are a good source of plain, well-fitting AA bras in smaller bands. Online, specialist small-bust brands make AA and AAA with cups shaped for a shallow bust. More suggestions in best bras for small busts.

Frequently asked questions

Is AA smaller than A?

Yes. In UK sizing AA is the cup below A. An A cup is a one-inch difference between bust and band, and an AA is less than one inch.

Is there a size smaller than AA?

Some brands make an AAA. It is uncommon in UK shops and found mainly in specialist small-bust and teen ranges.

Do I need to wear a bra with an AA cup?

Only if you want to. Nobody needs a bra for health reasons at any size. People with AA cups wear them for coverage, shape under clothes, comfort during sport, or simply because they like them.