B Cup Bras

A B cup means about a 2-inch difference between your bust and band measurements, since each cup letter adds roughly an inch. It's a relative size, so the cup only makes sense with a band number — a 30B holds less than a 38B. B sits one cup above A and one below C.

There's no single measurement, because the cup is relative to the band — a 30B is smaller in volume than a 38B. A B cup is defined by roughly a 2-inch difference between bust and band, placing it on the lighter side of average, between an A and a C.

A B cup is on the lighter side of average rather than truly small — it's one step up from an A and one below a C. How large it looks depends heavily on the band, since cup volume scales with band size: a 38B holds noticeably more than a 30B.

At the same band, a B cup is about one inch fuller than an A cup — roughly a 2-inch bust-to-band difference versus 1 inch. If your bras gape at the top, an A cup may fit better; if they feel snug, stay with B.

At the same band, a C cup is about one inch fuller than a B cup — roughly a 3-inch bust-to-band difference versus 2 inches. If you're spilling slightly or the cup feels tight, compare our C cup bras.

Try a sister size before changing cups — often the band is the real issue. Otherwise, moulded or lightly padded cups hold their shape and bridge the gap well. If bras consistently gape at the top, size down a cup; if they feel tight, size up.

Measure your band snugly around the ribcage just under the bust, then measure around the fullest part of the bust. A difference of about 2 inches indicates a B cup. Because sizing varies by brand, use the result as a starting point and check each brand's size chart.

Sister sizes hold the same cup volume with a different band. If the cup fits but the band is loose or tight, size across: 34B is close to 32C and 36A. Going down a band goes up a cup, and vice versa — the quickest fix when the band feels off.

No — the cup letter is relative to the band, so a 32B and a 36B hold different volumes even though both are "B." The letter reflects the bust-to-band difference, not an absolute size, which is why you always shop the full size (band and cup) together.

Essentially all of them. Push-up for shape and lift, t-shirt bras for everyday, plunge and demi for necklines, bralettes and wireless for soft natural comfort, and lace for lingerie looks. A B cup is light enough to skip heavy structure but full enough to fill out any style.

Yes — push-up is one of the most popular choices for a B cup. Light padding and angled cups add shape, lift and cleavage for a fuller look, while still sitting flat and comfortable. It's the easiest way to change your silhouette without changing size.

A smooth, lightly moulded t-shirt bra is the most versatile everyday choice — seamless under clothing and comfortable all day. A soft wireless style is a great alternative if you prefer no underwire. Get the band size right first, since that's what makes any bra sit correctly.

The band should sit snug and level around your body, the underwire should lie flat against the ribcage and enclose the breast, the straps shouldn't dig, and the cups should be smooth with no gaping or spillage. If any of those are off, adjust the band or try a sister size.

Hand-wash in cool water or use a mesh bag on a delicate cycle with the hooks fastened, never wring the cups, and lay flat or hang to dry. Rotating between a few bras and keeping them out of the dryer helps the elastic and shape last much longer.