A 34B bra size is a common bra size that combines a 34-inch band with a B cup. The number 34 refers to the approximate measurement around the ribcage, while the letter B represents the cup size. A 34B bra usually provides moderate coverage and support and is available in many styles, including T-shirt bras, wireless bras, sports bras, and padded bras. However, bra sizing can vary between brands, so a 34B in one brand may fit slightly differently in another. For the best fit, measure your underbust and bust and compare the measurements with the brand’s size chart.