The B cup is the most prevalent in America and, until recently, in the UK. Just how big a B cup is varies for either market. Wherever one buys underwear, however, knowing that a B cup is for you is crucial for fit, comfort and fashionable appearance.
Precisely How Big a B Cup Is
Cup size is measured by the difference between chest measurement above or below the breast (also called “band size”) and that around the fullest portion of the breast itself (“bust size”). By United States standards, a bust size 1.6 to 2.5 inches more than chest size determines how big a B cup is. Going by standards in the United Kingdom, you are a B cup if the difference between the two measurements is 1.1 to 2.0 inches.
Be aware that the American standard for cup sizes is calculated based on half-an-inch increments. The British standard is based on one-inch intervals. Since women are well aware that garment manufacturers play fast and loose with sizes, it is a comfort to the bra buyer that those measurement intervals coincide with the distance between the two or three eyes at the back onto which the hook goes.
Common Pitfalls When Figuring Out How Big a B Cup Is
It is best to take band size around the lower rib cage, under the breasts. Taking this around the neckline can yield exaggerated measurements of band size since the better-endowed a woman is, the greater the chance that her breasts start to become prominent at or around the second rib.
How big a B cup is can also change with pregnancy and the weight gain common to maturing women. A woman might refuse to believe that her current measurements have gone from a band size of 34 to 36. But if her corresponding bust size went from 36 to 38, she remains a cup B. Being in denial about weight gain, she insists on buying a 34-35B still. The result? Breasts spill over the neckline (instead of being comfortably covered by a full-cup model) or along the edges of both armholes. This is unsightly and is visible to others if one likes body-hugging tops.
Going on a diet can also change how big a B cup is. If the weight loss has gone on long enough, the difference between bust and band sizes might shrink from 2 to 1.5 inches. That small change can mean that insisting on cup B when buying a new bra will reveal it is too large. The outside of the cup wrinkles oddly and one can easily slip a finger in between the cup and breast.
Sizing up how big a B cup is means deducting bust size from band size. As long as the difference, the fullness of one’s bust is 1.1 to 2 inches (for UK lingerie) or 1.5 to 2.5 inches (in U.S. stores), then one can confidently opt for a B cup on the next purchase.